Compressor device with cooling and method for operating a compressor device

Abstract

The present invention relates to a compressor device having: a compressor for compressing a gas to generate a compressed gas; the cooling device comprises an oil cooler, at least one compressed air cooler and at least one shell cooler so as to cool a shell or a part of the shell of the compressor. The oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each provided for cooling by means of a coolant flow consisting of a liquid coolant, in particular water, for the coolant flow of the oil coolant, the coolant flow of at least one of the at least one compressed gas cooler and the coolant flow of at least one of the at least one housing cooler, an individualized, controllable control medium is provided in each case in order to control each of the coolant flows in an individualized manner, the cooling power can be individually controlled for at least one of the oil cooler, at least one of the at least one compressed gas cooler, and at least one of the at least one housing cooler.

Description

Field of the Invention

[0001] The present invention relates to a compressor device for compressing a gas to produce compressed gas, in particular compressed air, wherein the compressor device has a cooling device. Furthermore, the present invention relates to a method for operating a compressor device having a cooling device. Background Art

[0002] A compressor for compressing a gas to produce compressed gas can also be referred to as a compressed gas compressor. It is thus used to produce compressed gas, usually compressed air. The compressed air, or other compressed gas, is particularly provided for subsequent industrial applications. The following description of compressed air also meaningfully relates to other compressed gases.

[0003] Due to its function, heat is generated when producing compressed air. Not only the compressed air but also the compressor, in particular its housing, is heated and thus must be cooled. For cooling, a housing cooler can be provided to cool the housing of the compressor or a part thereof, which is usually also referred to as or configured as a shell-and-tube cooler. In it, a cooling medium, in particular water, which can also be synonymously referred to as a coolant, can flow through the housing cooler to cool the housing. Furthermore, a compressed gas cooler can be provided, which is arranged in a part of the pipeline system that guides compressed gas, in particular compressed air. Here, a heat exchanger can be specifically provided, and the cooling medium or coolant, in particular water, also flows through the heat exchanger. Usually, oil is also required when producing compressed gas, especially for lubricating the components of the compressor. This oil is also heated and can be cooled by an oil cooler, which can particularly have a heat exchanger. The cooling medium or coolant, in particular water, also flows through the heat exchanger.

[0004] Efficient cooling can be achieved by connecting all the mentioned coolers to a primary cooling circuit, and a plurality of the mentioned coolers are also provided respectively. In particular, the cooling devices can be used to be connected in parallel completely or partially, so that ideally the coolers do not receive the heated water from the upstream cooler, which would occur in a series connection.

[0005] By the parallel connection, each cooler obtains its share of cooling water according to the flow resistance of its parallel branch. By correspondingly designing the parallel branch or the cooler itself, each cooler obtains an appropriate amount of coolant, that is, in particular water.

[0006] It has been confirmed that the cooling demand and thus the demand for coolant, namely cooling water, fluctuates. To adapt to this situation, the flow of the coolant in the primary circulation circuit can be adjusted correspondingly. However, if the change in the coolant demand in each cooler is different, then in the case of optimal cooling in one cooler, there will be over-cooling or under-cooling in other coolers.

[0007] To adapt this non-optimal cooling, corresponding valves can be provided and adjusted. By means of these valves, the corresponding coolant inflow of each cooling device can be set. However, this adjustment would be time-consuming because the technician has to make or change the corresponding settings for this. The result also depends on the individual ability of the technician.

[0008] As a further improvement, individual cooling devices can be provided, where each cooler obtains its own cooling circulation circuit. However, this solution is costly and thus not absolutely recommended.

[0009] A cooling device for a compressor is known from the document WO 2022 / 163079 A1, in which the amount of cooling liquid can additionally be adjusted. Summary of the Invention

[0010] The present invention is therefore based on the object of solving at least one of the above problems. In particular, a solution is to be proposed in which a matching cooling for a compressor device is achieved in a simple manner and method by means of a cooling device. At least an alternative solution to the hitherto known solutions is to be proposed.

[0011] According to the present invention, a compressor device according to an embodiment of the present invention is proposed. Thus, the compressor device is provided with a compressor and a cooling device. The compressor, which can also be synonymously referred to as a compressed gas compressor, is provided for compressing a gas to produce compressed gas. In particular, a compressed air compressor for producing compressed air is proposed. The compressed air compressor produces compressed gas or compressed air in a generally known manner and method.

[0012] Furthermore, a cooling device is proposed, which has at least one oil cooler, a compressed gas cooler and a housing cooler. The oil cooler is provided for cooling the oil heated by the compressor. For this purpose, the oil can flow through a heat exchanger from the compressor in such a way that the oil outputs its heat to a liquid coolant, in particular water, namely cooling water.

[0013] The compressed gas cooler is provided for cooling the compressed gas, and multiple compressed gas coolers can also be provided. The compressed gas flows through the compressed gas cooler and outputs heat to the liquid coolant here. It is also considered that the compressor has multiple compression stages, so that the gas is at the first pressure level after the first compression stage, and this can already be regarded as compressed gas. However, in the range of the partially compressed gas, the compressed gas has not been compressed to the final pressure level yet. However, a compressed gas cooler can also be provided for the partially compressed gas (which can also be simply referred to as compressed gas as described above), and the compressed gas cooler can be arranged between two compression stages in this case. If there are at least two compression stages, then a compressed gas cooler can be provided again at least after the second compression stage, and the compressed gas cooler cools the compressed gas output by the mentioned second compression stage.

[0014] The housing cooler is provided for cooling the housing of the compressor or a part of the housing, and multiple housing coolers can also be provided. The overall design of the compressor or a part of it can be regarded as the housing of the compressor in principle. Therefore, it not only refers to the housing in the sense of the covering of the compressor, but also to the compressor as a physical object.

[0015] Therefore, for the coolers, it is proposed that the oil cooler, at least one compressed gas cooler and at least one housing cooler are each provided for realizing cooling through a coolant flow composed of a liquid coolant, especially water. Each of the mentioned coolers thus has at least one flow channel through which the coolant can flow. The mentioned coolers are thus subject to the principle of the following coolers, which use a coolant flow composed of a liquid coolant for cooling, that is, especially a cooler cooled by water or cooling water. During operation, the coolant flow thus flows through each cooler.

[0016] It is specifically proposed that for the coolant flow of the oil cooler, the coolant flow of at least one of the at least one compressed gas coolers and the coolant flow of at least one of the at least one housing coolers, individual and controllable control mechanisms are respectively provided to individually control each coolant flow so that the cooling power can be individually controlled for the oil cooler, at least one of the at least one compressed gas coolers and at least one of the at least one housing coolers. The control mechanism is controllable, which means that the control mechanism can be controlled via open-loop control or closed-loop control, that is, non-manually. It can also be called automatically controllable. In order for the control mechanism to be controllable, the control mechanism can, for example, have a control input through which the control mechanism can receive a control signal.

[0017] It is also considered that, for example, one of the coolers in a cooler, such as a compressed gas cooler, has two or more sub-coolers or is divided into two or more sub-coolers, such as being divided into an intercooler and a secondary cooler, and the two sub-coolers can be controlled via control mechanisms respectively. For each of the two or more sub-coolers, the corresponding coolant flow is thus controllable. The sub-coolers can be connected in parallel with each other for this purpose. The individual control of the coolant flow through each of the sub-coolers can thus be shut off, so that additionally or only, the distribution of the total coolant flow to the sub-coolers can be controlled.

[0018] For example, two shell coolers, which can also be referred to as shell-and-tube coolers, can be connected in parallel, so that the coolant flow is distributed to the two shell coolers, and only one control mechanism is provided for the two shell coolers together. The control mechanism controls the shell coolers, thereby controlling each individual shell cooler or the associated coolant flow, and such a control does not depend either on the control of the coolant passing through the oil cooler or on the control of the coolant passing through the cross-flow compressed gas cooler.

[0019] Preferably, a primary cooling circuit is provided for all coolers in such a way that the coolers are connected in parallel with each other completely or partially. However, this does not exclude that, for example, two coolers, such as two shell coolers that can be configured as shell-and-tube coolers, are connected in series. Such two serially connected shell coolers can also be regarded as a common shell cooler. If two or more sub-coolers are connected in parallel with each other, it is considered that the sub-coolers are connected in series with the remaining coolers or a part thereof in the primary cooling circuit, so as to obtain the total coolant flow of the primary cooling circuit, but the individual control can still be achieved through their parallel connection with each other.

[0020] In any case, it is proposed that, although there is a possibility of still using a common primary cooling circuit, individual controllability is proposed. Therefore, each individual control mechanism can be configured as a controllable valve, or a controllable pump, or some individual control mechanisms are configured as controllable valves and other individual control mechanisms are configured as controllable pumps. Thereby, continuous adjustment of the coolant flow of each cooler is possible, so that each cooler can operate at its optimal operating point. That is, each cooler can operate optimally. If, for example, there is an increased cooling demand for the oil cooler, its coolant flow can be increased, while the coolant flow of the remaining coolers can also be increased.

[0021] Conversely, it is recognized that optimal cooling does not necessarily mean cooling down as much as possible, but rather that its ability to output or absorb moisture also particularly depends on the temperature of the compressed gas. If the compressed gas, especially compressed air, is cooled down too strongly, then it absorbs less moisture or tends to output moisture. If this is not desired, then this is prevented or promoted in other cases through corresponding cooling control. Thus, it is also possible to individually reduce the cooling power of the cooler while the cooling power of the remaining coolers remains unchanged or is optimized. This is considered, for example, in the case where the cooling water volume flow is limited or a certain (minimum) water discharge temperature leaving the entire facility is required.

[0022] Here, it has been particularly recognized that the proposed individual control causes that not only the oil cooler but also at least one housing cooler and also at least one compressed gas cooler or their coolant flows can be controlled independently of each other. Thereby, optimal cooling for each cooler is possible, which can also include minimizing the overall required cooling power. It should be noted here that when using a common primary cooling circuit, the common coolant flow, i.e., the sum of the coolant flows of the individual coolers, must be recooled, and this common cooling medium flow can therefore also be referred to as the total cooling medium flow. If there is too strong cooling in the cooler, then this overall causes heat input into the total cooling medium flow or the sum cooling medium flow, and this can cause the recooler of the primary cooling circuit to extract more heat from the common cooling medium flow, i.e., it must be recooled.

[0023] It is also important that the clearance between the compressor housing and the rotor is kept within an optimal range. Too strong cooling of the housing causes shrinkage and thus contact between the rotor and the housing, whereby the clearance will continuously increase. When the housing is cooled too little, an unnecessarily large clearance is created between the rotor and the housing, which can cause internal reflux of the already compressed gas.

[0024] It is also important that the compressed air is cooled to an optimal value after the last compressor stage. When there is too little cooling, component damage may occur or the drying of the compressed air may not function sufficiently.

[0025] For the oil cooler, it is important to keep the oil viscosity within an as optimal range as possible via the oil temperature. When the oil is overcooled, the power consumption increases, and when the oil is overheated, the losses increase.

[0026] Through the proposed solution, it is thus also possible to overall reduce the required recooling. But usually more important is the lower electrical power consumption and the optimal compressed air discharge temperature.

[0027] Generally, a high temperature in the total coolant flow or the sum coolant flow is desired. Then as much heat as possible should be transferred to the heating water, which can be coupled to or use the total coolant flow or the sum coolant flow, for example to save fuel costs for heating. For this purpose, however, the temperature level must be increased correspondingly so that the cooling water can be used for heating purposes, which would be negative more precisely for the cooling of the compressor, but would make sense in the case of a corresponding heat demand. Thereby, the input costs can also be reduced.

[0028] In particular, it is proposed to provide or control an individualized control mechanism for non-manual control and / or automatic control and / or control by a control program.

[0029] According to one aspect, an oil cooler, at least one compressed gas cooler, at least one of which should be present multiple times, and at least one housing cooler, at least one of which should be present multiple times, are connected to a common coolant circulation circuit, in particular a primary cooling circulation circuit, in particular completely or partially in parallel connection.

[0030] The advantages thereof have been described. Therefore, it is also possible to provide only one common coolant circulation circuit, so that only one aftercooler can also be used. However, here, common heat dissipation is particularly important in order to be able to achieve as complete a utilization of heat as possible. Nevertheless, the possibility of individualized control of each cooler is still achieved. Therefore, although it is a common coolant circulation circuit, individualized control of each of the mentioned coolers is feasible.

[0031] This particularly has the advantage that when improving the existing system and partly also the existing infrastructure, only the individualized control mechanism has to be added to each cooler, which lies in the planning or retrofit. This of course does not exclude that after or together with this optimization, savings can also be made in the common coolant circulation circuit, such as the mentioned smaller design or size of the aftercooler for the common coolant circulation circuit or the primary cooling circulation circuit.

[0032] According to one aspect, a compressor has a plurality of compression stages and at least one compressed gas cooler has an intercooler and a secondary cooler. The intercooler is arranged between the first and second compression stages and cools there the gas partially compressed to the compressed gas, i.e., the compressed gas, which has not yet reached the maximum pressure level set in the overall system. Additionally, the secondary cooler is arranged at the output of the compressor, i.e., at the output of the last cooling stage. In the case of two compression stages, the secondary cooler is thus arranged after the second compression stage. There, the secondary cooler cools the compressed gas having the final pressure level of the compressed gas, i.e., the pressure level after the second compression stage. In particular, it is proposed here that the intercooler and the secondary cooler each have controllable control means that can be individually manipulated, or at least one is associated with each of them. Thereby, the intercooler and the secondary cooler can also be controlled individually. They can also be connected in parallel with each other and / or relative to the remaining coolers for this purpose.

[0033] According to one aspect, the control means each have a controllable valve and / or a controllable pump.

[0034] With the controllable valve, the control means can be realized in a simple manner and method. The controllable valve applicable to all control means can be controlled centrally via a control device in order to thus achieve overall control. The controllable valve only requires minimal control energy and is thus cost-effective not only during purchase but also during operation. By throttling the valve, a higher pump power is required, and the pump power is then throttled again. For the energy costs of the water circulation, an individual pump can be more economical.

[0035] One of the advantages is that it closes hermetically. It can be advantageous for a plurality of compressors to operate at a common cooling system, but not all compressors always operate simultaneously. During shutdown, the valve can be closed so that there is no unwanted flow-through.

[0036] Although the controllable pump can be more costly than the controllable valve because it is an active device in this regard, good control results can be achieved thereby. In particular, when using a controllable pump, the coolant flow separately controlled thereby does not depend on or only slightly depends on the total coolant flow present. If all individual control means are configured as controllable pumps, the pump for pumping the total coolant flow can also be dispensed with. Nevertheless, even if one variant is often more advantageous, a combination is also feasible.

[0037] According to one aspect, at least one housing cooler has at least one shell-and-tube cooler, in particular having two sub-shell-and-tube coolers connected in series, for cooling each a compressor stage, which compressor stages are arranged for cooling the same coolant flow and controlling the coolant flow with the same control means.

[0038] In such a shell cooler, a medium line is thus provided in the jacket area of the compressor. Thereby, the compressor is flowed through by the corresponding coolant flow and thus cooled.

[0039] In the proposed series-connected sub-shell coolers, in particular, the sub-shell cooler can cool the jacket of the compressor of the first compression stage, and the second sub-shell cooler cools the second compression stage. In a preferred design, the colder water first flows through the second stage because the shell temperature and thus the shell size, in particular the size of the gaps, act more strongly on the reflux here. It has thus been recognized that, due to the geometry of the compressor, it is meaningful for the second stage to be flowed through first.

[0040] By means of the series connection, in the case of the same cooling water volume flow for jacket cooling, due to the higher flow velocity, better heat transfer can be achieved than in a parallel connection, and thus a better cooling effect can be achieved.

[0041] Preferably, the jacket cooling obtains an excessively large amount of cooling water, such that the preheating of the coolant in the second stage is less important for the first stage.

[0042] It is meaningful here that the two sub-shell coolers are combined into a shell cooler, thus being considered as a shell cooler and also being controlled by only one control mechanism.

[0043] Here, it is also based on the recognition that the two compression stages are also, in principle, subject to similarly strong loads and can thus be controlled jointly. The coordinated and comprehensive control of the two shell coolers for these two compression stages is thus recognized as appropriate. It has thus been recognized, in particular, that not every individual control need be advantageous.

[0044] According to one aspect, a common control device is provided for the coordinated control of the coolant flow, in particular such that the common control device is arranged for the control of the control mechanism and is connected to the control mechanism.

[0045] Thereby, it can be achieved that not only can each cooler itself be well controlled, but also the coordination between the coolers can be achieved, and in particular the overall cooling concept can be achieved. It has also been recognized here that, in particular when using a common aftercooler for all coolers and / or when using a common primary cooling circuit for all coolers, the coordinated control of the coolant flow can additionally be achieved, taking into account the requirements on the aftercooler or on the primary cooling circuit or by the aftercooler or by the primary cooling circuit. In this way, for example, the temperature at the outlet of the common primary cooling circuit and / or in the aftercooler can also be taken into account and even adjusted.

[0046] A common control device can control all control mechanisms and is connected thereto for this purpose. This connection particularly relates to a data technology connection. The connection can be wired, which is usually appropriate since all the coolers mentioned are usually close to each other in terms of location. If necessary, some components can be farther apart, such as, for example, a aftercooler, especially when the aftercooler is designed as a cooling tower in one embodiment. A wired communication and thus a wired connection can then also be provided between the common control device and the control mechanisms, but a wireless connection, particularly a radio connection, is also considered.

[0047] The common control device can in particular be set up for controlling the control mechanisms in such a way that the control device receives actual values from the control mechanisms and / or transfers setpoint values to the control mechanisms. Preferably, the control device can be connected to other sensors, particularly to temperature sensors, but also to humidity sensors, which can be provided for detecting the moisture of compressed air or compressed gas. Other characteristics of the compressed air can also be detected and transferred to the common control device for further consideration.

[0048] The common control device can furthermore be connected to control mechanisms that control, for example, a primary cooling circuit, i.e., in particular the flow-through of the primary cooling circuit. Other control tasks are also considered, such as other control tasks for other or secondary common cooling circuits to be provided.

[0049] Thus, through the common control device, comprehensive control and thus the implementation of the overall concept are possible without requiring a high equipment construction. In particular, the control mechanisms can be designed as controllable valves and then only require control instructions from the common control device. This solution enables comprehensive control possibilities while only requiring a small equipment construction at the same time. The same applies when one or more of the control mechanisms are designed as pumps. Here, although the pumps are also required, they do not generally constitute a high equipment cost and can be controlled via the common control device in a simple manner and method.

[0050] Overall, an optimal cooling result can be achieved for the common compressor device. It should be repeated here that the optimal cooling result does not mean maximum cooling, but the optimal cooling result can also be considered in view of the consumption used. For example, a compressor with two compressor stages can be provided and furthermore an intercooler and a secondary cooler. The desired temperature in the finished compressed gas can be achieved by strong cooling of the secondary cooler and weak cooling of the intercooler, or vice versa.

[0051] In particular, it has been recognized that it is advantageous to cool the intercooler and the secondary cooler differently in a targeted manner. In particular, controllable control mechanisms are also proposed for this.

[0052] In particular, it has been recognized that it is possible to achieve or benefit from as optimal cooling as possible by cooling the compressed air in the secondary cooler only as strongly as necessary, in particular such that a sufficient pressure dew point can be achieved and the compressed air is as warm or reliable as possible, but at the same time cooling the compressed air in the intercooler as strongly as possible, since the drive power of the compressor is thereby reduced.

[0053] The housing temperature can also influence the compressed air temperature, and the compressed air temperature can influence the housing temperature. For example, the following control correlations have been recognized. Through good intercooling, the discharge temperature from the first compressor stage can also be reduced. That is, it has been recognized that in the case of a low temperature between the compressor stages, the intermediate pressure also drops there, so that the compression ratio of the first compressor stage drops, which can cause a lower temperature at the output of the first compressor stage.

[0054] The cooling of the partially compressed compressed air (or more generally compressed gas) can at least also act on the housing temperature, in particular also on the rotor temperature of at least the second compressor stage, through which the cooled partially compressed compressed air also flows.

[0055] Thus, finally, all cooling temperatures can influence each other and in particular jointly influence the overall cooling result of the compressor device. Through a common control device, all of these can be coordinated. Then an optimal compressed gas result can be achieved. Thereby, the electrical power consumption of the compressor can also be influenced.

[0056] Thereby, it is also possible to achieve a high temperature level at the water outlet of the total coolant flow or the sum coolant flow, whereby the heat can be further utilized.

[0057] According to one aspect, it is proposed that the compressor is a dry-compression compressor and / or a screw compressor. A screw compressor is a compressor configured to compress a gas, in particular the air to be compressed, by the movement of two screws engaged with each other. Thereby, in particular, a continuous compression process can also be carried out.

[0058] In a compressor that can also be configured for dry compression of a screw compressor, there is no oil for the compression process, and in particular, no oil is injected into the compressed gas or the gas to be compressed into a compressed gas. It has been recognized that such a dry-compression compressor can heat up more strongly than other compressors, especially because the cooling effect of the injected oil is eliminated. The application fields are in the following ranges where oil-free compressed air is required, such as in the pharmaceutical industry, food industry, cleanroom applications, etc. Here, oil contamination of the compressed air is not allowed at all. This application can thus still be cooled well by the proposed solution without the risk of contamination. Therefore, in particular, for such a dry-compression compressor, the concepts mentioned according to this embodiment and any other embodiment are proposed. In particular, the use range of the dry-compression compressor can be broadened by the proposed cooling concept. In particular, the electrical power consumption of the compressor can be reduced. A higher water discharge temperature in the total coolant flow can be achieved, enabling better utilization of the accumulated waste heat.

[0059] According to one aspect, it is proposed that there is at least one additional or two additional compressed gas coolers, which are arranged downstream of the compressor with respect to the flow direction of the compressed gas in order to further cool the compressed gas there. In this regard, it is proposed that at least one additional or two or more additional compressed gas coolers are connected to the same primary cooling circuit as at least one of the coolers already mentioned, that is, the same primary cooling circuit as one or more compressed gas coolers and / or one or more housing coolers and / or oil coolers. Thereby, further cooling of the compressed gas can be carried out, and by using the other compressed gas coolers at the same primary cooling circuit, a well-distributed cooling for compressing the gas can be achieved without the need for high equipment costs.

[0060] With the additional compressed gas cooler, it is possible for other heat exchangers to be cooled at a higher level by means of the primary cooling system, here for example by means of heating water. It has been recognized that it can be meaningful to operate the primary water system at a higher temperature in order to be able to utilize more heat, but at the same time to produce very dry and / or cold compressed air.

[0061] It is particularly emphasized here that such use of so many compressed gas coolers can only be achieved, or at least significantly improved, by controlling the individual coolant flows through the proposed control mechanism. In the case where there is no such individual control mechanism for each of the compressed gas coolers, there is a risk that an unnecessarily large amount of cooling water will flow through the heat exchanger. Manual setting must always take into account the most unfavorable situation, such as in midsummer at maximum power. Then there is a risk that the compressed air will generally be cooled unnecessarily strongly. As a result, the operating volume flow decreases, so that more compressed air will be consumed in many applications.

[0062] It is thus proposed in any case that each compressed gas cooler, i.e. also other compressed gas coolers, respectively use a coolant flow controlled separately by respective individualized control means. The respective individualized control means are thus control means for controlling the corresponding coolant flow. In other words, in the case of four compressed gas coolers, four control means are also provided, i.e. one control means is provided for each compressed gas cooler. The compressed gas coolers can also be controlled coordinately via a common control device.

[0063] Furthermore or alternatively, it is proposed that at least one or more additional compressed gas coolers are connected to a second medium cooling circuit, which can be referred to as a secondary cooling circuit. The secondary cooling circuit can operate independently or be coupled to the primary cooling circuit, in particular via a heat exchanger.

[0064] Thereby, the supplementation of the one or the more additional compressed gas coolers can be carried out in a simple manner and method. It can be supplemented and controlled via the respective medium cooling circuit, i.e. the second medium cooling circuit, i.e. the secondary cooling circuit. Via the secondary cooling circuit, heat can be withdrawn from the primary cooling circuit via a heat exchanger when required. Thereby, the inlet temperature into the primary cooling circuit can be reduced, which results in better cooling and lower electrical power consumption. At the same time, however, significantly less waste heat can also be utilized. The second medium cooling circuit can be referred to as a secondary cooling circuit. Such a secondary cooling circuit can thus be provided for cooling the primary cooling circuit and additionally cooling the aforementioned additional compressed gas coolers, i.e. supplying coolant. The secondary cooling circuit thus has a dual function.

[0065] According to one aspect, it is proposed that the oil cooler, at least one compressed gas cooler and / or at least one housing cooler each have a heat exchanger or are configured as a heat exchanger, and are arranged to control the respective coolant flow, as the coolant flow through the respective heat exchanger, by respective control means.

[0066] It thus becomes particularly clear that in the case of using a heat exchanger (which is considered for one or more or all of the mentioned coolers), the control means respectively control the flow rate through the respective heat exchanger. Thereby, the heat exchanger can thus be controlled, and thus the cooling power of the corresponding cooler can be controlled.

[0067] According to one aspect, a compressor device, in particular a cooling device, is provided for individually controlling a coolant flow depending on the temperature. The provision of the compressor device or the cooling device can in particular consist in providing a corresponding temperature sensor and a corresponding control algorithm. In particular, a common control device can be connected to the corresponding temperature sensors in order to receive temperature values from the temperature sensors thereby. A corresponding control, in particular a corresponding control program, can be implemented on the common control device, which control program issues at least one control command depending on one or more received temperature signals for output to the control means respectively, or is provided for this purpose.

[0068] Each coolant flow can be controlled by the control means and the control means can receive the corresponding control commands. The control commands can be created by the control mentioned depending on at least one temperature value.

[0069] In particular, it is proposed that the control takes place depending on at least one temperature from a list having the following temperatures:

[0070] - oil temperature, in particular the oil temperature of the oil heated by the compressor,

[0071] - compressed gas temperature,

[0072] - jacket temperature of the coolant flowing through the housing jacket of the compressor,

[0073] - coolant temperature,

[0074] - oil inlet temperature, as the temperature of the oil entering the oil cooler,

[0075] - secondary cooler - gas outlet temperature, as the temperature of the compressed gas leaving the secondary cooler or the secondary cooler,

[0076] - intercooler - gas outlet temperature, as the temperature of the compressed gas leaving the intercooler or the intercooler,

[0077] - intercooler - coolant outlet temperature, as the temperature of the coolant leaving the intercooler,

[0078] - secondary cooler - coolant outlet temperature, as the temperature of the coolant leaving the secondary cooler,

[0079] - shell cooler - coolant outlet temperature, as the temperature of the coolant leaving the jacket cooling device or the jacket cooling device,

[0080] - each a gas or coolant outlet temperature, as the temperature of the compressed gas or the coolant leaving at least one heat exchanger, and

[0081] - Compressor - Gas discharge temperature, being the temperature of the compressed gas leaving the compressor's compressor stage and / or the compressor and / or the compressor unit.

[0082] In particular, it is respectively proposed that the corresponding temperature be measured by means of a sensing device. Thereby, it is feasible to automatically prepare and consider the temperature.

[0083] The oil temperature is thus the temperature of the oil heated by the compressor. This oil can be used particularly as a lubricant in the compressor and it gets heated by the operation of the compressor. It has been recognized that temperature-related cooling control can correspondingly achieve the regulation of the oil temperature, so that not only good cooling can be ensured, but also it is avoided that the oil is cooled too strongly. The temperature of the oil also has an impact on its viscosity, such that overly cold oil is not necessarily desirable. The temperature regulation of the oil of the compressor, which can also be simply referred to as compressor oil, can be achieved in a simple manner and method by the proposed control mechanism.

[0084] Similarly, the control can be carried out according to the compressed gas temperature, that is, according to the temperature of the compressed gas, in particular compressed air. Thereby, it is thus also possible to control the compressed gas temperature. In particular, it has been recognized here that the compressed gas should not be overheated, for which cooling is proposed, but the compressed gas should also not be overly cold.

[0085] The jacket temperature of the coolant flowing through the compressor's housing jacket also gives information about the cooling achieved by the compressor. The measurement can be carried out directly inside the housing, but this is not necessarily the case. The measurement is typically carried out at the outlet or at a higher position outside the housing. In any case, the jacket temperature of the coolant can give good information about the overall temperature of the compressor, that is, not limited to the point-like temperature at a specific measurement point in the compressor.

[0086] The temperature of the coolant can generally also be recorded at different locations. The said temperature can give information about the cooling effect of the corresponding cooler to which it belongs. In particular, the temperature of the coolant after discharging from the corresponding cooler should be used here in order to evaluate the cooling power and / or temperature in the corresponding cooler.

[0087] In addition or alternatively, the temperature of the coolant before flowing into the cooler can also be used. Particularly advantageously, the difference between the inlet and outlet temperatures of the coolant in the cooler is used, from which the cooling power of the cooler can be derived.

[0088] The oil inlet temperature, which is the temperature of the oil entering the oil cooler, can be advantageously considered in order to control the coolant flow thereby. If the oil inlet temperature is very low, then a smaller coolant flow can be sufficient, or even no coolant flow is provided. On the other hand, a higher coolant flow can make sense. The optimal oil temperature can be related to different factors, such as the compressor speed and the type of oil used. In a compressor with speed regulation, the optimal oil temperature can vary slightly continuously during operation with the current speed. It has been recognized that all of these can be taken into account by the proposed solution, in particular by considering the oil temperature.

[0089] The secondary cooler - gas outlet temperature is the temperature of the compressed gas leaving the secondary cooler. It gives information on how well the secondary cooler can cool the compressed gas. In particular, when the secondary cooler - gas outlet temperature is too high, especially when it is too high for subsequent components or processes, the coolant flow can be increased through the secondary cooler. In any case, it is proposed to open - loop control or closed - loop control the coolant flow through the secondary cooler based on the secondary cooler - gas outlet temperature.

[0090] The inter - cooler - gas outlet temperature represents the temperature of the compressed gas leaving the inter - cooler. Thereby, the cooling result of the inter - cooler can be detected. In particular, it is proposed to control the coolant flow through the inter - cooler based on the inter - cooler - gas outlet temperature.

[0091] The inter - cooler - coolant outlet temperature is the temperature representing the temperature of the coolant at the outlet of the inter - cooler. In particular, it is proposed to control the coolant flow through the inter - cooler based on the inter - cooler - coolant outlet temperature. In particular, it is proposed to reduce the coolant flow of the inter - cooler when the inter - cooler - coolant outlet temperature decreases. Here, in particular, it has been recognized that in the case of a small inter - cooler - coolant outlet temperature, the coolant in the inter - cooler does not absorb enough heat, so it flows through the inter - cooler almost too fast. Therefore, the coolant flow can be reduced.

[0092] It behaves completely analogously in the case of the secondary cooler - coolant outlet temperature, which represents the temperature of the coolant leaving the secondary cooler. Here, it is also proposed to control the coolant flow through the secondary cooler based on the secondary cooler - coolant outlet temperature. Preferably, the coolant flow through the secondary cooler is regulated based on the gas outlet temperature leaving the secondary cooler.

[0093] The jacket cooler - coolant outlet temperature describes the temperature of the coolant leaving the jacket cooler. Here, preferably, the coolant flow through the shell - and - tube cooler is also controlled based on the jacket cooler - coolant outlet temperature. The lower the jacket cooler - coolant outlet temperature, the less heat it absorbs from the compressor per unit of flow - through volume, and this indicates that the coolant flow is too high.

[0094] It is also proposed to consider the gas or coolant discharge temperature separately and to control according to it. The gas discharge temperature is the temperature of the compressed gas leaving the heat exchanger. The coolant discharge temperature is the temperature of the coolant leaving at least one heat exchanger. In both cases, the result of the heat exchanger can be evaluated via the corresponding temperature. In the case of a high gas discharge temperature leaving the heat exchanger, it should be assumed that there is little cooling through the heat exchanger. In the case of a small increase in the coolant temperature (which is read considering the coolant inlet temperature compared to the coolant discharge temperature), it is to be assumed that the residence time of the coolant in the heat exchanger is too short and can at least be extended, or in other words, the volume flow of the coolant through the heat exchanger is too high or unnecessarily high and can be reduced or throttled if necessary.

[0095] It is particularly advantageous to consider the gas discharge temperature and the coolant discharge temperature of each heat exchanger together. If the gas discharge temperature is low or the gas discharge temperature is only slightly higher than the coolant inlet temperature of the corresponding heat exchanger, then there is a good cooling result. If at the same time the coolant discharge temperature is also low, it can be deduced therefrom that the cooling of the compressed gas through the heat exchanger can also be achieved with a smaller coolant flow. It is proposed specifically for an absolute evaluation to compare the expected value with the actual value. However, if the gas discharge temperature is high, especially higher than the corresponding expected value, the coolant flow may still have to be increased, even when the coolant discharge temperature is already low. If the gas discharge temperature is high and the coolant discharge temperature is high, then poor cooling can be inferred and this can then be improved by increasing the coolant flow, because in this case, a high coolant discharge temperature can infer a high residence time of the coolant in the heat exchanger. The coolant flow can be increased in this case.

[0096] The compressor - gas discharge temperature is the temperature of the compressed gas leaving the compressor's compressor stage. It can represent the compressed gas leaving the compressor unit. It has been generally recognized that the compressor - gas discharge temperature can be used to set the coolant flow related thereto. If the temperature is high, it makes sense to increase the coolant flow, respectively through the compressor stage involved where the compressor - gas discharge temperature is high. Also considered here is to increase the coolant flow through the corresponding jacket cooler of the compressor stage involved where the compressor - gas discharge temperature is correspondingly high.

[0097] However, other considerations are also taken into account. The compression final temperature is first related to the corresponding compression ratio. In addition, the rotational speed and the stage state have a decisive influence.

[0098] Intermediate cooling can also have a decisive influence, not only on the downstream stages, but also on the upstream stages. An attempt is made to optimally cool the jacket cooling device over a long period. This can mean that the jacket cooling device remains at a similar temperature throughout the year. If the jacket cooling device is better cooled in winter, this only has minor advantages, which are overcompensated in summer due to poor cooling, thus larger clearances and more recirculation. The cooling circuit - coolant discharge temperature is the temperature of the coolant when it is discharged from the primary and / or secondary circuit. At this temperature, in principle, the heat absorption of all coolers connected to the primary or secondary cooling circuit can be read out as a cumulative result. If the cooling circuit - coolant discharge temperature is high, it makes sense to control the corresponding aftercooler so that it increases its cooling power. It is also considered to influence the total coolant flow through the primary or secondary cooling circuit, especially the higher the cooling circuit - coolant discharge temperature, the higher this common coolant flow is set.

[0099] Thus, in particular, the coolant discharge temperature can be adjusted to a desired value. The desired value for the coolant discharge temperature can be selected such that the operation proceeds as efficiently as possible. This means consuming little cooling water, for example in the case of fresh water cooling, or maintaining a preset inlet temperature, for example in the form of a so-called discharge well or river, or adjusting the temperature for optimizing the cooling tower. Generally, a high coolant discharge temperature is also desired in order to achieve an available temperature level, i.e., in order to be able to use the waste heat for other processes, such as for heating, adsorption refrigeration, drying processes, feed water preheating, etc.

[0100] In particular, the coolant heating can be adjusted to a specific value.

[0101] In particular, it is proposed to consider not only the mentioned temperatures, but also multiple such temperatures. In particular, at least one temperature is considered for each cooler used. Preferably, the temperature is detected and evaluated at each cooler in order to control the coolant flow in relation thereto. For example, if all coolant flows have too high a temperature, it would be appropriate to increase the total coolant flow. If only individual temperatures are high, for example the temperature of the coolant flow of one cooler at the outlet is high while the temperature of the coolant flow of another cooler is low, then this is actually due to uneven cooling between the observed coolers. In this case, as an example, the flow rate of the high-temperature coolant can be increased. According to another example, the total coolant flow can be restricted, or a predetermined water discharge temperature can be preset. In this case, it is proposed not only to increase the coolant flow through one cooler, but at the same time to reduce the coolant flow through another cooler in order to keep the mixed total discharge temperature constant.

[0102] It is proposed in any case to carry out the control at least according to one of the temperatures mentioned. In particular, it is proposed to take into account a plurality of the temperatures mentioned and in particular to control at least one coolant flow or the total coolant flow according to a plurality of the temperatures mentioned, in particular according to two, three, four, five or more of the temperatures mentioned. For this purpose, in particular, a common control device can be used.

[0103] According to one aspect, it is proposed that the compressor device is arranged to control at least one coolant flow according to the pressure dew point of the compressed gas. In particular, for this purpose, the pressure dew point is measured by means of a sensing device such that it can be used for further processing in the control device. It has been recognized in particular that in this way the moisture absorption of the compressed gas can be controlled. If the compressed gas, in particular compressed air, is cooled below its pressure dew point, then moisture will condense, which is undesirable, but can also be controlled purposefully such that the pressure dew point is reached. According to a design, the cooling device, in particular one, several or all coolant flows, is controlled such that the compressed gas is not cooled below its pressure dew point in order to thereby avoid moisture condensing out of the compressed gas, in particular out of the compressed air.

[0104] According to another preferred design, it is proposed that the compressed gas is cooled such that the downstream dryer reaches the desired dew point or deviates slightly, for example by 1 to 5 Kelvin. This is proposed for the following reasons.

[0105] The compressed gas is strongly cooled as required before entering the dryer in order to reach the desired dew point, but not more than necessary. The aim here is that the compressed air has the most optimal temperature possible after the dryer, i.e. as warm as possible, but not too warm and is sufficiently dry.

[0106] From this, the available coolant volume flow can be distributed such that the total specific power consumption is minimized. This means that the power consumption of at least the compressor, dryer and cooling system is minimized with respect to the generated compressed gas volume flow or compressed gas mass flow.

[0107] This control according to the pressure dew point is particularly recommended in the presence of a drying device. In this case, the cooling device is controlled such that the temperature of the compressed gas drops such that the pressure dew point is reached or is almost reached before the compressed gas enters the drying device.

[0108] The following example based on an adsorption dryer serves for illustration. Thus, a pressure dew point below -20 °C can be required. The dryer achieves this value only for an inlet temperature of the compressed air below +50 °C, where it should be noted that this value is also related to the pressure and the regeneration temperature and other variables. Thus, compressed air at, for example, 200 °C is cooled to 50 °C, so that condensate also accumulates here and is separated as completely as possible. Thereafter, 100% relative humidity can be present, thus a pressure dew point of 50 °C. Thereby, the dryer achieves a pressure dew point of -20 °C.

[0109] If cooled too strongly, for example to 30 °C, the dryer reaches a pressure dew point of, for example, -35 °C. The energy consumption of the dryer only drops slightly here. Thus, it can be more efficient to use slightly more cooling water for intercooling and jacket cooling and supply a small amount of water to the secondary cooler for cooling.

[0110] Thereby, it can be achieved that in the drying device the compressed gas outputs moisture to the drying device as easily as possible, i.e., with the least possible energy input. In particular, the colder the compressed air is when entering the dryer, the smaller the pressure dew point achievable in the dryer. When a condensate separator and a condensate discharger are installed upstream of the dryer, the moisture load of the dryer can also be smaller with a colder inlet temperature into the dryer.

[0111] Furthermore, in the following, the pressure dew point, which can also simply be referred to as the dew point, is considered. For the downstream process, the dew point after the dryer can be decisive. It is considered that the pressure dew point is adjusted after the dryer, i.e., at the outlet or at the transfer point to the application of the compressed gas, not only in a refrigeration dryer but also in an adsorption dryer, by adjusting the temperature before the dryer. Additionally, other measures can be proposed, which are described in DE 102014 019805 B3.

[0112] In the regulation cascade, the inlet temperature into the dryer is still derived from the pressure dew point after the dryer. By means of the condensate separator before the dryer, the pressure dew point and the temperature can be almost the same here. This can be expressed intuitively as adjusting the dew point before the dryer, where, however, only the temperature before the dryer is measured and not the dew point before the dryer, because temperature measurement is significantly simpler.

[0113] According to one aspect, a compressor device, in particular a cooling device, is provided for controlling a coolant flow such that the total coolant discharge temperature is adjusted to a preset desired discharge temperature as the temperature of the coolant leaving the primary and / or secondary cooling circuit. The primary cooling circuit and the secondary cooling circuit supply a cooler connected with cold coolant, and the coolant is then heated by the coolant flow respectively controlled by the corresponding cooler in the respective cooler. The thus heated coolant flow then flows together again in the primary cooling circuit or the secondary cooling circuit and forms a total coolant flow, which is discharged from the primary or secondary coolant circuit at a specific location. The temperature of the leaving coolant, i.e., the total coolant discharge temperature, is detected at the outlet, and it is thus determined entirely by the heating process that each coolant flow has undergone through its respective cooler.

[0114] It can be particularly meaningful here to continue using the total coolant flow, for example, for heating, or to impose other requirements on the temperature of the outflowing total coolant flow, for example, for discharging into a river.

[0115] On the other hand, too low a total coolant discharge temperature indicates excessive cooling, which is not desirable because the recooling device can no longer cool down an excessive volume flow with too low a temperature difference to the desired temperature, or because of the cooling water cost, especially when using fresh water, or the pump power and the ventilation device power together with the associated cost increase. However, for the compressor, good intermediate cooling and good jacket cooling are helpful. For the dryer, good cooling after the second compressor stage is also helpful. But unnecessarily strong cooling is inefficient.

[0116] Therefore, it has been recognized that it is advantageous to adjust the total coolant discharge temperature to a preset desired discharge temperature. Thereby, in particular, it is ensured that there is sufficient cooling and also efficient cooling. Additionally, the higher the temperature level, i.e., the higher the total coolant discharge temperature, the better the waste heat can be utilized if necessary.

[0117] The compressor device or the cooling device is thus configured to control the coolant flow such that it has a corresponding control program, which can receive the relevant temperature as a measured value and output a control command for controlling the relevant control mechanism accordingly. Such a control program can be implemented on a corresponding process computer of the compressor device, in particular the cooling device, and the process computer has a corresponding interface to receive the required temperature values and output the control values to be output.

[0118] The desired value for closed-loop or open-loop control can be preset by a higher-level control device, i.e., by a common control device. Thus, for example, the coolant discharge temperature of the total coolant flow can be preset by a heating control device according to the external temperature via the heating curve of the building to be heated.

[0119] According to one aspect, it is proposed that the compressor device, in particular the cooling device, is configured to control the coolant flow of the oil cooler by means of a relevant control mechanism such that the preset oil temperature is adjusted. In particular, it has been recognized that efficient operation can be achieved by adjusting the specific oil temperature that can be preset correspondingly. It can be achieved that the oil temperature is not too high, so that the compressor does not overheat, but the oil temperature is also not too low and the optimal viscosity of the oil for lubricating the bearings and the transmission is achieved, whereby the efficiency of cooling and / or compressor operation may deteriorate. In the case of overcooled oil, the viscosity of the oil is too high, so that in addition the resistance in the bearings is too high, which will cause higher power consumption. In the case of continuously overcooled oil, in addition, an increased water content will occur in the oil, which will have an adverse effect.

[0120] The compressor device or the cooling device can thus be configured to control at least one coolant flow of the cooler to adjust the corresponding temperature, such that a process computer is provided on which the corresponding control is implemented. The process computer can have an input interface and an output interface for this purpose. Temperature values can be received via the input interface and control values can be output via the output interface, in particular to a relevant control mechanism.

[0121] According to one aspect, it is proposed that the coolant flow of at least one compressed gas cooler, in particular the secondary cooler, is controlled by means of a relevant control structure such that a preset compressed gas discharge temperature is not exceeded and / or not fallen below. In particular, it is proposed that the compressed gas does not overheat, and this can be achieved by controlling the coolant flow of the corresponding compressed gas cooler. In particular, it is proposed that the coolant flow of at least one compressed gas cooler, in particular the secondary cooler, is controlled such that the compressed gas is not cooled more strongly than necessary.

[0122] In addition or alternatively, it is proposed that the coolant flow of at least one housing cooler, in particular a jacket cooler, is controlled such that the coolant discharge temperature of the coolant is lower than the coolant discharge temperature of at least one of the compressed gas coolers, in particular the intermediate cooler. In particular, it has been recognized that in this way a good distribution of cooling can be achieved and these two different coolers, namely the housing cooler and the compressed gas cooler, can be coordinated with each other. In particular, it is proposed to optimally use the available cooling water and in particular to minimize the specific power [kWh / m 3 . Both jacket cooling and intermediate cooling have an important influence on the generated compressed gas volume flow and power consumption, which is exploited hereby.

[0123] In principle, a low coolant discharge temperature of the coolant can be achieved by increasing the coolant flow. Here, therefore, the coolant flow through the shell cooler can be increased until the discharge temperature is lower than the discharge temperature of the coolant in the intercooler. Then, a correspondingly large cooling power is achieved via the shell cooler, which also reduces the temperature of the compressed gas or at least the partially compressed compressed gas.

[0124] It has been particularly recognized here that jacket cooling can have a significant effect on the specific power. In the case of optimal cooling of the housing, the housing has an optimal size such that the gap is minimized. If the housing becomes hotter relative to the rotor because it is cooled less well, then the gap between the rotor and the housing, but also the gap between the two rotors, becomes larger. As a result, more of the already compressed gas flows back from the chamber into the previous chamber. Thereby, the required gas mass flow is reduced, the power consumption increases and the gas becomes hotter.

[0125] Intercooling also has an effect on the specific power. The higher the temperature at the inlet of the second compressor stage, the higher the corresponding intermediate pressure. The reason for this is that the volume flow of the second compressor stage remains constant, but at a higher gas temperature, this volume flow is reached at a higher pressure. The mass flow is already preset by the first compressor stage.

[0126] Therefore, it can be avoided that the first compressor stage has to be compressed to a higher pressure than when the intercooling is poorer.

[0127] According to one aspect, the coolant flow of at least one shell cooler, in particular a jacket cooler, is controlled such that the difference between the coolant discharge temperature when the coolant leaves the shell cooler and the coolant inlet temperature when the coolant enters the shell cooler

[0128] - is lower than a predefinable first value, and / or

[0129] - is higher than a predefinable second value, and / or

[0130] - is between a predefinable third and fourth value.

[0131] It has been particularly recognized here as advantageous to provide a programmed minimum temperature rise.

[0132] It has been recognized here that in many cases it is good to cool as well as possible, i.e., to conduct as much water as possible. But it has also been recognized that this can, however, have a limit from which it is no longer meaningful because the additional expense is no longer in proportion to the use. Although as much cooling water as possible is advantageous for the gas compression process, it requires a large amount of cooling water or pump power.

[0133] If the volume flow of water used for jacket cooling is doubled in order to refer to an intuitive example and thus the water temperature rise is reduced from 40 K to 20 K, then this is generally meaningful and economical. However, if the volume flow of water used for jacket cooling is doubled in order to refer to another example and thus the water temperature rise is reduced from 2 K to 1 K, then this is no longer very meaningful or economical, because the additional cost in terms of water, i.e., for cooling, exceeds the savings in terms of gas, i.e., for compressing the gas.

[0134] According to one aspect, adjusting to a minimum temperature rise of the cooling water is achieved at least as a sub - aspect in the case of one, several or all heat exchangers. It has the greatest practical significance in jacket cooling but is also important in the remaining coolers, also in oil coolers.

[0135] In some coolers, if an unattainable gas temperature is preset, i.e., for example, if it is preset that the compressed gas temperature is less than the coolant temperature of the total coolant flow at its inlet, then adjustment to the minimum temperature rise can be made.

[0136] Another reason for adjusting to the minimum temperature rise is recognized to be that an excessive water volume flow or too high a flow velocity can cause damage. However, if there is no measuring device for the flow velocity, then this can be evaluated via the temperature rise. As long as the minimum temperature rise is reached, it can be ensured that the maximum allowable flow velocity is not exceeded even at maximum power.

[0137] According to the invention, a method for operating a compressor device is also proposed. The compressor device herein includes a compressor for compressing a gas to produce a compressed gas, in particular compressed air, and a cooling device, and the cooling device includes an oil cooler for cooling the oil heated by the compressor, at least one compressed - gas cooler for cooling the gas that is completely or partially compressed into the compressed gas, and at least one housing cooler for cooling the housing of the compressor or a part of the housing, wherein the oil cooler, at least one compressed - gas cooler and at least one housing cooler are each cooled by a coolant flow composed of a liquid coolant, in particular water, and wherein each coolant flow is individually controlled by an individual, controllable control structure such that the cooling power is individually controlled for the oil cooler, at least one compressed - gas cooler and at least one housing cooler respectively.

[0138] The method according to the invention thus uses a compressor device having a compressor and a cooling device as described above in the context of the aspect of a compressor device having a compressor and a cooling device. At least one compressor device according to one of the above aspects is used.

[0139] This method thus works as also described above in the context of the embodiments of the compressor device. In particular, the method steps to be performed by the compressor device or the cooling device are carried out in accordance with the method according to the invention or in accordance with aspects of the method according to the invention.

[0140] It is thus particularly proposed that the method according to the invention for operating a compressor device uses a compressor device according to at least one of the aspects described above. Description of the Drawings

[0141] In the following, the invention will be explained in detail by way of example with reference to the drawings according to embodiments.

[0142] Figure 1 Schematic view showing a compressor device according to the prior art,

[0143] Figure 2 Schematic view showing a partial view of a compressor device,

[0144] Figures 3 to 8 Schematic view showing a compressor device according to an embodiment of the invention respectively,

[0145] Figure 9 Schematic partially sectional view showing a compressor device having two compressor stages,

[0146] Figure 10 Showing Figure 9 An enlarged view of the first compressor stage of the compressor device. Detailed Description of the Embodiments

[0147] Figure 1 There is shown a compressor device 100 having a compressor 130 which has first and second compressor stages 131 or 132. The compressor 130 and also the remaining elements are shown schematically.

[0148] Furthermore, there is provided an intercooler 133 and a secondary cooler 134, which can also be referred to as a compressed air intercooler or a compressed air secondary cooler. The intercooler is shown here as part of the compressor 130 since it is arranged between the first and second compressor stages, but it can also be configured as a separate element. Correspondingly, the secondary cooler 134, which is not shown as part of the compressor 130, can be part of the compressor in another design.

[0149] For cooling the first and second compressor stages 131, 132, there is provided a first or second jacket cooling device 141 or 142. The jacket cooling devices 141 and 142 are integrated into the compressor stages 131 or 132 respectively.

[0150] Furthermore, an oil cooler 135 is provided. The oil cooler 135 is connected to the oil circulation circuit 145 of the compressor 130. For better overview, the connection between the oil circulation circuit 145 and the compressor 130 is not shown in this figure and furthermore also in most of the other figures.

[0151] For cooling the compressor device 100 in general, a primary cooling circulation circuit 150 is provided, which has a coolant inflow section 151 and a coolant return section 152. The mentioned coolers, namely the intercooler 133, the secondary cooler 134, the first and second jacket coolers 141, 142 and the oil cooler 135 are supplied with cold coolant, in the illustrated example water, via the primary cooling circulation circuit, namely via the coolant inflow section 151. The water heated up by the cooler in this way flows back via the coolant return section 152 into the heat sink 154, which is only shown abstractly. The heat sink 154 can, but does not have to be, a part of the compressor device 100 any longer. A primary heat exchanger 156 is provided in or as the heat sink, and the common coolant flow in the primary cooling circulation circuit 150 can be achieved by a primary coolant pump 158.

[0152] The mentioned coolers, namely the intercooler 133, the secondary cooler 134, the first and second jacket coolers 141, 142 and the oil cooler 135 are connected in parallel in the primary cooling circulation circuit. Thereby, all the mentioned coolers are supplied with coolant by the primary cooling circulation circuit 150. The respective cooler is connected in parallel to the primary cooling circulation circuit via an intercooler branch 163, a secondary cooler branch 164, a jacket cooler branch 166 or an oil cooler branch 165.

[0153] The jacket cooler branch 166 thus supplies the first and second jacket coolers 141, 142 first. In the example according to Figure 1 the first and second jacket coolers 141, 412 are connected in parallel here.

[0154] To set the coolant flow or its relationship to each other, manually adjustable valves are provided, namely a manual intercooler valve 173, a manual jacket cooler valve 176 and a manual oil cooler valve 175. To better coordinate the intercooler 133 and the secondary cooler 134 with each other, a secondary cooler regulating valve 174 is provided.

[0155] Furthermore, a primary regulating valve 159 is provided, which can control the return of the total coolant in the coolant return section.

[0156] Furthermore, an oil bypass valve 185 is also provided, by means of which the flow of oil can be controlled through the oil cooler 135.

[0157] Figure 1Therefore, a cooling concept with improved functionality is shown. In particular, it has been confirmed that the individual coolers are at least partially poorly coordinated with each other and cool to different extents. It has been recognized that there is a need for improvement here in order to achieve good, uniform and thus efficient cooling for the compressor device 100. It has also been recognized that there is a need for a matched cooling for each cooler, which need can also depend on the operating state of the compressor device, in particular its cooling device. In particular, the need for a matched cooling can depend on the final pressure, on the rotational speed, on the suction temperature, on the cooling water inlet temperature T10, on the desired cooling water discharge temperature at the temperature measuring point T14.

[0158] It should be noted that the compressor device 100 thus consists of the compressor 130 and the plurality of mentioned coolers together with the primary cooling circuit, where the mentioned coolers together with the mentioned primary cooling circuit (and possibly other secondary cooling circuits) can be understood as the cooling device of the compressor device.

[0159] In particular, the following disadvantages are obtained:

[0160] The distribution of the water volume flow to the parallel coolers has to be set manually, but the distribution of the heating power and thus the water temperature fluctuates significantly depending on the operating point.

[0161] When the desired discharge temperature at the temperature measuring point T14 is high, the oil cooler and the jacket cooling have to be cooled separately by means of cooling water, which can be carried out via the secondary cooling system.

[0162] Due to various disturbing variables, significant deviations can occur between the individual discharge temperatures T11, T12, T13, T16.

[0163] Generally, an inefficient use of the cooling water is obtained. A stepwise damage caused by overcooled cooling water is possible.

[0164] Similarly, the following is determined to be disadvantageous.

[0165] The water discharge temperature is controlled via the common valve V14.

[0166] The oil temperature is closed-loop controlled via a bypass to the oil cooler. The oil cooler usually receives unnecessarily much water so that the oil cooler can still be cooled sufficiently even in the most unfavorable case.

[0167] The secondary cooler usually receives unnecessarily much water so that the secondary cooler can still be cooled sufficiently even in the most unfavorable case. Via the valve V12, only the temperatures T11 = T12 are balanced in order to be able to compensate for the different heat powers in the secondary cooler.

[0168] The jacket cooling device usually receives too little water to be able to reach the desired discharge temperature T14 - but sometimes also receives too much and too cold water, which can cause damage to these stages.

[0169] The intermediate cooling device only receives enough water to reach the desired mixed discharge temperature T14.

[0170] If the component temporarily requires better cooling, then V14 remains open so that all heat exchangers receive more water, but no longer reaches the desired water discharge temperature T14.

[0171] Figure 2 Shows a part of the compressor device together with the primary cooling circulation circuit 250, which in principle can correspond to Figure 1 the primary cooling circulation circuit 150. Figure 2 Particularly illustrates the primary cooling circulation circuit 250. It can be controlled via the primary regulating valve 259 in order to supply the connected coolers with coolant, and the primary regulating valve can correspond to Figure 1 the primary regulating valve 159. The flow rate through the primary cooling circulation circuit 250 can be controlled via the primary regulating valve 259. Thereby, various connected coolers, especially various connected heat exchangers, are also controlled. In particular, the oil cooler 235 configured as a heat exchanger here is supplied with coolant through the primary cooling circulation circuit 250. There is also a parallel branch 290, which is connected in parallel with the cooling section supplying the oil cooler 235 and can in particular supply the remaining Figure 1 mentioned coolers, that is, it can in particular supply the intermediate cooler 133, the secondary cooler 134, and the first and second jacket coolers 141, 142.

[0172] The primary cooling circulation circuit 250 can be connected to a heat sink via an interface 292, as shown in Figure 1 it.

[0173] Therefore, referring to Figure 2 , hitherto in the dry rotor, there has been a regulating valve V14 in the primary circulation circuit 250, and the primary regulating circuit jointly regulates the flow rate through a plurality of parallel heat exchangers.

[0174] There is only a manual valve to set the distribution of the flow rate.

[0175] Only the heat exchanger for stage 2 already has its own regulating valve because the deviation is the largest here.

[0176] Figure 3 Shows a compressor device 300 according to a design. The compressor device 300 is exactly similar to Figure 1The compressor device 100 has a compressor 30, which has first and second compressor stages 1, 2, and which has first and second jacket coolers 41, 42. The first and second jacket coolers 41, 42 are connected in series with each other in the illustrated embodiment.

[0177] Furthermore, an intercooler 3 and a secondary cooler 4 are provided, which cool the compressed gas respectively. The intercooler 3 cools the partially compressed compressed gas here, while the secondary cooler 4 cools the fully compressed compressed gas.

[0178] An oil cooler 5 is likewise provided, which cools the oil flowing through the compressor 30.

[0179] All the mentioned coolers 3, 4, 5, 41 and 42 are connected to a primary cooling circuit 50, which thus supplies the coolers with coolant. In order to operate the primary cooling circuit - similar to that shown in Figure 1 - a primary heat exchanger 10 and a primary coolant pump 12 are provided. The primary heat exchanger 10 and / or the primary coolant pump 12 can respectively form or not form part of the compressor device.

[0180] According to the invention, it is now proposed that each of the cooling elements connected to the primary cooling circuit 50 can be controlled non - manually, in particular via a controllable control means, via its own, i.e. individualized, control means. For this purpose, regulating valves V11, V12, V13 and V16 are respectively provided, which are respectively arranged in coolant branches connected in parallel with the primary cooling circuit in order to control the coolant flow through the respective cooling elements. The regulating valves can simply be referred to as valves in this and all other embodiments. The serially connected coolers are thus respectively combined into cooling elements. The intercooler 3, the secondary cooler 4 and the oil cooler 5 thus respectively form cooling elements. The first and second jacket coolers 41 and 42 are thus combined into a common jacket cooler 341, which thus forms a cooling element and is controlled via the regulating valve V13. Alternatively, individual valves are also possible.

[0181] The cooling elements mentioned, i.e. the intercooler 3, the secondary cooler 4, the oil cooler 5 and the jacket cooler 341, can thus be individually controlled, so that a coordinated cooling concept for the compressor device 300 can be achieved.

[0182] In particular, it is proposed that in order to control the respective cooling elements or for this purpose to control the regulating valves V11 to V13 and V16, the temperature of the coolant, i.e. the cooling water, is also detected and taken into account. For this purpose, corresponding temperature measuring sites T10 to T16 are provided. The cooling can thus be coordinated with each other and this is carried out according to the corresponding temperature of the cooling flow including the total coolant flow of the primary cooling circuit 50.

[0183] Additionally, other temperatures can also be detected, and for this, in the Figure 3 embodiment, the oil temperature is detected by means of the temperature measurement site T60. Other temperatures can also be detected, in particular at least one temperature of the compressed gas, which is indicated by the temperature measurement site T51. T100 here is the same discharge temperature leaving the compressor device in the said drawing, for which T51 is also provided. However, it is also possible to detect the temperature of the compressed gas at other sites, including at sites where the compressed gas has not yet been fully compressed, in particular between the first and second compressor stages 1, 2 or also at a site before the first compressor stage 1.

[0184] Preferably, all these temperatures can be incorporated into the control of the cooling device and thus into the control of the regulating valves V11 to V13 and V16. However, it is not necessary to take into account all temperatures. Preferably, at least one temperature is considered.

[0185] According to Figure 3 the compressor device thus has a compressed air intercooler 3, a compressed air aftercooler 4, an oil cooler 5 and stages 1, 2 with jacket cooling devices 41, 42.

[0186] In the said embodiment, there is a cooling water circulation circuit 50, which has a heat exchanger 10, for example for heat recovery. The heat exchanger 10 can be used for waste heat utilization, but a cooling system not used for waste heat utilization can also be used.

[0187] However, in the case of combined waste heat utilization, the benefit is particularly great.

[0188] Via four regulating valves V11, V12, V13 and V16, the water volume flow can be set individually and optimally through the components 3, 4, 5, 1, 2 or 41, 42.

[0189] Closed-loop control of the (mixed) water discharge temperature T14 of the compressor is possible via the above-mentioned valves V11, V12, V13, V16.

[0190] In particular, it is proposed that the temperatures after the first and second compressor stages are thus incorporated at the measurement sites T11 and T12 according to the drawing in order to exclude the formation of bubbles and the associated risks.

[0191] It is proposed to incorporate at least one oil temperature, for example at the measurement site T60, into the control in order to closed-loop control the water volume flow through the oil cooler. Alternatively, component temperatures, such as the outer bearing ring temperature, can be used.

[0192] In particular, it is preferably proposed that the inlet temperature of the compressed gas into the second compressor stage is thus especially at Figure 4The measurement site T31 shown in the figure is incorporated into the control together to protect the second compressor stage from overheating.

[0193] It is particularly preferably proposed to incorporate the discharge temperature of the coolant when it leaves the jacket cooler of the first or second compressor stage into the control, that is, the temperatures at the measurement sites T13 and T15 according to the corresponding figure. The above is proposed to exclude the formation of bubbles.

[0194] It is preferably proposed to incorporate the discharge temperature of the compressed gas when it leaves the compressor device into the control together. This can be the temperature at the measurement site T100 according to the corresponding figure. It is proposed that this can be incorporated together during individualized closed-loop control and optimization.

[0195] The mixed water discharge temperature, that is, the discharge temperature of the total coolant flow, that is, the temperature at the measurement site T14 according to the corresponding figure, is recognized as important and it is proposed to incorporate it into the control together.

[0196] The temperatures at the measurement sites T100, T14 and T60 are also recognized as important. Particularly preferably, they are incorporated into the control together.

[0197] Furthermore, it has been recognized that for each valve, at least one temperature sensor, especially the corresponding measurement site, is beneficial for closed-loop control. Therefore, it is proposed to be provided with the temperature sensor and it is especially incorporated into the control together.

[0198] For controlling the valve V11, it is proposed to use at least one, multiple or all of the temperatures at the measurement sites T14, T11 and / or T31. Preferably, in addition, the temperature of at least one measurement site among the measurement sites T2 and T4, T12 and T10 shown in Figure 4 and other measurement sites if necessary can be used.

[0199] For controlling the valve V12, it is proposed to use at least one, multiple or all of the temperatures at the measurement sites T100, T14, T12 and / or T51. Preferably, in addition, the temperature of at least one measurement site among the measurement sites shown in Figure 4 and other measurement sites if necessary or the temperatures T52 and T85 and M85 or other temperatures can be used.

[0200] For controlling the valve V13, it is proposed to use one, multiple or all of the temperatures at the measurement sites T13, T15 and / or T23 partially shown in Figure 4 Preferably, in addition, the temperature of at least one measurement site among the measurement sites T2 and T4, T14 or T29 and T10 or T20 partially shown in Figure 4 and other measurement sites if necessary can be used.

[0201] It is proposed to control the valve V16 using at least one oil temperature, in particular at least one of the temperature measurement sites T60 and / or T66 shown partly in Figure 1 . Additionally or alternatively, at least one representative component temperature, such as the bearing temperature, can also be used. Preferably, furthermore, the temperatures at the measurement sites T16, T14 or T29 and T10 or T20 shown partly in Figure 4 can be used, and if necessary the temperatures of other temperatures or other measurement sites.

[0202] Subsequent figures describe other embodiments, but for better overview, the same reference numerals as in Figure 3 are used partly for the embodiments, in order to better show the correlation. However, this is not necessary, as these elements are actually the same. If, for example, a third or fourth compressed gas cooler is added to the intercooler and the secondary cooler, then it is considered that the intercooler and the secondary cooler are designed to be of smaller size correspondingly. Nevertheless, for better overview, in the subsequent embodiments, the same reference numerals 3 and 4 are also used for the intercooler and the secondary cooler respectively.

[0203] Figure 4 An embodiment of a compressor device 400 is shown, which is provided with a jacket cooler heat exchanger 6 for the first and second jacket coolers 41, 42. The jacket cooler heat exchanger can also be simply referred to as a heat exchanger. The jacket coolers 41, 42 are connected in series here, but the coolant flow through the jacket coolers 41, 42 is driven by a jacket cooler pump 14, thereby driving its own cooling circuit called the compressor cooling circuit, because the coolant flows through the corresponding jacket areas in the first or second compressor 1, 2. The jacket cooler pump 14 is thus a cooling water pump for the compressor cooling circuit 32. The compressor cooling circuit 32 is guided through the heat exchanger 6, i.e., through the primary side of the jacket cooler heat exchanger 6. The coolant flows through the secondary side of the jacket cooler heat exchanger 6 from the primary cooling circuit 50. The corresponding coolant flow of the primary cooling circuit 50 through the jacket cooler heat exchanger 6 is controlled by a regulating valve V13.

[0204] Preferably, the valve V13 is controlled according to the temperatures T13 and / or T15. Then the temperature T23 is obtained. The temperature at the measurement site Txx can also be simply and synonymously referred to as the temperature Txx hereinafter and above.

[0205] The temperatures T13 and / or T15 are regarded as more relevant relative to T23. However, alternatively, T23 can be used.

[0206] There is a risk of steam formation not only at the temperature measurement location T13, but also at the temperature measurement location T15. Therefore, it is proposed to measure the temperature there.

[0207] During cold start, V13 remains closed, so that there is no coolant flow at T23. At the temperature measurement location T23, no elevated temperature is thus obtained.

[0208] The temperature measurement locations T13 and T15 are preferably placed directly at the higher outlet. Thereby, an increase in temperature can be detected even without active circulation, so that the jacket cooler pump can be switched on first in relation thereto. Thereby, a forced flow is obtained at the temperature measurement locations T13 and T15, thus enabling a positive temperature measurement. However, the valve V13 can remain closed, so that no measurement can be carried out during this period, and thus closed-loop control is not possible. If the temperature T13 and / or T15 further increases, then the valve V13 is opened by the control device, which can also be referred to as "opening by closed-loop control". Subsequently, the temperature at the measurement location T23 can be used for closed-loop control.

[0209] The regulating valve V13 can be referred to as a jacket cooler regulating valve and it controls the coolant flow through the jacket cooler heat exchanger 6. The valve V13 controls the coolant volume flow for the jacket cooler heat exchanger 6. In other designs, it can also control the coolant volume flow for the jacket coolers 41, 42. The valve V13 controls the temperatures T13 and T15, and if necessary other valves are used for one or more jacket coolers. The volume flow for the jacket cooling devices 41, 42 is controlled by the jacket cooling pump 14 in the Figure 4 design shown.

[0210] Figure 4 Furthermore, a second and a third secondary cooler 7, 8 are shown, which can also be referred to as a second and a third compressed air secondary cooler or compressed gas secondary cooler, or simply as a heat exchanger, since it is preferably implemented as a heat exchanger. It is arranged in the compressed gas line 34, i.e., downstream of the compressed gas and behind the secondary cooler 4 or the compressed gas secondary cooler 4. Thereby, additional cooling of the compressed gas can be achieved.

[0211] Particularly preferably, as also in Figure 4As shown in the embodiments, a dryer, in particular an adsorption dryer 20, is used to compress a gas, and the dryer is incorporated into the compressed gas line 34. In a refrigerated dryer, an additional secondary cooler is also meaningful in order to control the dew point and the discharge temperature via a closed loop. However, in the case of a refrigerated dryer, as shown, the dryer secondary cooler 8 is less meaningful. In a refrigerated dryer, the heat exchanger 8 can rather be used to heat the compressed air. Therefore, the use of an adsorption dryer is particularly proposed here. In an adsorption dryer, the heat exchanger 8 is particularly used to cool the compressed air.

[0212] It is particularly proposed here that the compressed air dryer 20 is arranged in the flow direction of the compressed gas behind the second secondary cooler 7 and in front of the third secondary cooler 8.

[0213] In order to control the coolant flow through the second secondary cooler 7 and the third secondary cooler 8, regulating valves V25 or V28 are respectively provided. Therefore, the second and third secondary coolers 7, 8 can even be controlled independently of each other.

[0214] Additionally, temperature measuring sites T25 or T28 are respectively provided and are associated with the second or third secondary coolers 7, 8 and thus the corresponding regulating valves V25 or V28.

[0215] It has been particularly recognized here that the dryer can be supported by means of the second heat exchanger 7, so that the pressure dew point after the dryer can be influenced. However, the discharge temperature leaving the dryer also decreases thereby, which is sometimes desirable but sometimes not.

[0216] By means of the heat exchanger after the dryer, the compressed air can be brought to an optimal temperature for the downstream application. In an adsorption dryer, the air at the outlet is significantly hotter than the air at the inlet, such that cooling is required again here.

[0217] The regulating valve V25 for controlling the coolant flow through the second secondary cooler 7 can control the coolant flow according to the temperature detected by the temperature measuring site T25. However, preferably, the air discharge temperature T52 is controlled in a closed loop by means of the valve V25. The desired value for the temperature T52 in a facility with a dryer is derived from the desired pressure dew point after the dryer via a closed-loop control cascade. In a facility without a dryer, the desired value for the temperature T52 is derived from the desired value for the temperature T100 that can be preset externally.

[0218] Closed-loop control after the temperature T25 or after the temperature difference T25 - T20 is also feasible according to another design.

[0219] The regulating valve V25 thus controls the coolant flow according to the discharge temperature at which the compressed air leaves the second secondary cooler 7 at the temperature measuring site T52.

[0220] It is also proposed that the regulating valve V28 for controlling the coolant flow through the third secondary cooler 8 be closed-loop controlled to the Figure 6 compressed air discharge temperature T86 or T100 shown in. According to an alternative design, a closed-loop control is proposed after the temperature T28 or the differential temperature T28 - T20.

[0221] This can thus be carried out according to the temperature of the temperature measuring point T28, i.e., it is feasible to control the coolant flow according to the coolant temperature at the output of the third secondary cooler 8.

[0222] For the second and third secondary coolers 7 and 8, a secondary cooling circuit 80 is provided for supplying coolant.

[0223] The secondary cooling circuit 80 can output heat again via the secondary heat exchanger 11, and its coolant flow can be driven via the secondary coolant pump 13. Through the secondary cooling circuit, cooling can be carried out as independently as possible by the second and third secondary coolers 7 and 8, i.e., independently of the remaining coolers and independently of the primary cooling circuit.

[0224] In the illustrated embodiment, it is additionally proposed that the secondary cooling circuit 80 cools the coolant flow of the primary cooling circuit, in particular the total coolant flow, and for this purpose a corresponding primary-secondary heat exchanger 9 is provided. For control, in addition, a regulating valve V10 is provided, which is therefore arranged in the coolant branch of the primary-secondary heat exchanger 9. The control of the regulating valve V10 can be carried out according to the follow-up temperature of the coolant leaving the primary-primary heat exchanger 9. For this purpose, a temperature measuring point T10 is provided. The temperature of the coolant flowing through the regulating valve V10 can be detected at the temperature measuring point T24.

[0225] It is also proposed that in the Figure 4 illustrated embodiment, the primary coolant pump 12 according to Figure 3 be split, i.e., instead thereof, two primary coolant pumps 12a and 12b are provided, i.e., one before the primary-secondary heat exchanger 9 and the other after the primary-secondary heat exchanger 9. In addition, a primary circuit bypass 21 can be provided, via which a part of the total coolant flow of the primary cooling circuit 50 flows past the primary heat exchanger 10. By means of the internal pump 12b, in cooperation with the bypass 21 and the heat exchanger 9, the operation of the compressor can be maintained, so that the compressed air supply can be maintained even when the external heat sink 10 and / or the pump 12a are not available. This can be the case, for example, during maintenance work or renovation measures or also in case of seasonal heat requirements.

[0226] The external pump 12a is designed in particular for external pressure losses, i.e., in the heat exchanger 10 and in the pipelines and possibly other components. The internal pump 12b can operate together for support or can also be ready only for demand situations. When the primary coolant pump 12a does not supply water or supplies too little water, the internal pump is then switched on, and otherwise the compressor would overheat and a shutdown would occur.

[0227] Furthermore, a pressure dew point temperature measuring site M85 is provided after the drying device 20. Therefore, the pressure dew point temperature is determined at this site and cooling can be controlled in relation thereto. In particular, it is proposed to control the second secondary cooler 7 and / or the valves V25 and / or V28 according to the pressure dew point temperature.

[0228] In particular, the pressure dew point after the dryer is important. At the inlet of the dryer, the compressed air is usually saturated up to 100%. Therefore, the temperature and the pressure dew point are almost the same here, provided that the condensed water that has dropped is separated and discharged as completely as possible before the dryer.

[0229] For the drying result, in particular the temperature of the compressed gas at the inlet of the dryer is important.

[0230] If the condensed water is not separated before the dryer, the drying result is slightly worse. However, the compressor should be designed such that the condensed water that has already dropped has been separated beforehand.

[0231] The condensate separator and discharger are partly not shown in the drawing for reasons of simplification.

[0232] In addition, in Figure 4 the embodiment, it is proposed that some other temperatures are still recorded compared to the Figure 3 embodiment. For this purpose, in particular, temperature measuring sites T1 to T100 are provided, as long as they are drawn in Figure 4 .

[0233] In the following, some main aspects of the embodiment according to Figure 4 are particularly summarized.

[0234] According to Figure 4 the compressor device thus also has two additional coolers 7, 8.

[0235] In this embodiment, there are two cooling water circulation circuits 50, 60, and the coolers and the jacket cooling devices are distributed to these two cooling water circulation circuits.

[0236] The secondary circulation circuit 80 can have a cooling tower 11 for heat dissipation, which is a preferred example.

[0237] Via two control valves V25 and V28, it is also possible to individually and optimally set the water volume flow through the additional coolers 7, 8.

[0238] When adjusting the valves, the measured pressure dew point M85 is also taken into account here, so that the pressure dew point is optimized. To set the pressure dew point, valves V25 and V12 are actuated.

[0239] For actuating valve V28, the discharge temperature T100 is particularly suitable. The temperature T100 is also affected by valves V25 and V12.

[0240] Figure 5 The embodiment of... is again based on the embodiment according to... Figure 3 and is supplemented therewith by a secondary cooling circuit 580, but the secondary cooling circuit is only provided for cooling the total coolant flow of the primary cooling circuit 50. In this regard, the design of the secondary cooling circuit 580 corresponds to the design of the secondary cooling circuit 80 according to... Figure 4 especially in terms of its connection via the primary-secondary heat exchanger 9.

[0241] In the embodiment according to... Figure 5 no primary bypass 21 as shown in... Figure 4 is provided, but it is still considered to use such a primary bypass here as well.

[0242] Figure 5 The embodiment of... additionally provides a primary bypass regulating valve V19, which can also be simply referred to as the bypass valve V19, and via this primary bypass regulating valve, a part of the total coolant flow of the primary cooling circuit 50 can be fed to the intermediate cooler 3 and the secondary cooler 4 through the first and second jacket coolers 1, 2 and the oil cooler 5 before interception - according to one embodiment also after interception. In this regard, Figure 5 the embodiment of... Figure 3 and Figure 4 the embodiment of... differ in that the intermediate cooler 3 and the secondary cooler 4 can only directly obtain a part of the cooling flow that has not been heated by the oil cooler 5 and the first and second jacket coolers 41 and 42 via the primary bypass regulating valve V19. In the said embodiment of... Figure 4 that is, the heat already absorbed by the coolant in the oil cooler 5 and in the first and second jacket coolers 41 and 42 is also guided through one of the two compressed gas coolers, namely the intermediate cooler 3 or the secondary cooler 4, unless a part of the coolant flow is guided past it via the primary bypass regulating valve V19.

[0243] This is proposed as an optimized wiring for waste heat utilization at high temperature levels. The oil cooler and the jacket cooling device hereby obtain the maximum volume flow including the yet un-preheated primary water having also the temperature T10.

[0244] The primary bypass regulating valve V19 is especially used during cold start. When the oil has not yet reached the operating temperature, the primary bypass regulating valve V19 is closed. In the case of still cold coolant, i.e. cold water, having low temperatures especially at the temperature measuring points T10, T13, T15, the regulating valve V13 can also be closed. However, it has been recognized that the valves V11 and V12 should already control a sufficient water flow very quickly after cold start. Therefore, it is proposed to open the valve V19 during cold start. During operation, when the cold start process is ended, it is proposed that the bypass valve V19 is closed slightly again so that the oil cooler and the jacket cooling device can obtain a relatively high cooling water volume flow.

[0245] The water discharge temperature preset at the measuring point T14, i.e. the desired temperature, can only be obtained from the mixing of the sub-coolant flows having the temperatures T11 and T12. In these two coolers, a higher discharge temperature can be achieved. In particular, a high discharge temperature T14 can hereby be achieved.

[0246] It has been recognized that the following advantages are obtained.

[0247] The waste heat of the oil cooler and the jacket cooling device can be provided for waste heat utilization, even in the case of water temperatures where this has not been possible hitherto.

[0248] A higher desired temperature for the discharge temperature T14 can be achieved because only the sub-coolants having the temperatures T11 and T12 or at the measuring points T11 and T12 are mixed, hereby obtaining a mixing temperature which is not mixed out by the coolant having the temperatures T16 and T15.

[0249] Therefore, high temperatures and at the same time high power can be achieved with the water system for which a hot water system would otherwise be required.

[0250] The following summarizes some main aspects of the embodiment according to Figure 5 of the embodiment does not have an additional cooler. Figure 5 The embodiment according to

[0251] Herein there are again two cooling water circulation circuits 50, 580.

[0252] The coolers 3, 4, 5 of stages 1, 2 and the jacket cooling device are in the primary circulation circuit 50. Herein, first there is a parallel connection of the oil cooler 5 of stages 1, 2 and the jacket cooling device. Subsequently, the intercooler 3 and the secondary cooler 4 are connected in series. They are also connected in parallel with each other.

[0253] The secondary circulation circuit 580 hereby cools the primary circulation circuit 50 as needed.

[0254] The described wiring variant offers particular advantages in terms of heat recovery via the heat exchanger 10, which can also be referred to as waste heat utilization.

[0255] According to Figure 6 The embodiment corresponding to Figure 4 differs in that the second secondary cooler 7 and the third secondary cooler 8 in parallel connection are connected to the primary cooling circulation circuit 50. A secondary cooling circulation circuit 580 is also provided, which is configured as in Figure 5 and is coupled to the primary cooling circulation circuit 50.

[0256] The intercooler 3 and the secondary cooler 4, which can also be referred to as the first secondary cooler 4 in this embodiment and the remaining embodiments, are connected to the primary cooling circulation circuit 50 not in parallel but in series, as in Figure 5 the embodiment, in which the coolant is fed from the primary cooling circulation circuit 50 to the intercooler and the secondary cooler after flowing through the remaining coolers. The primary bypass regulating valve V19 shown in Figure 5 is dispensable here, because there is always, in particular, sufficient water volume flow through the second secondary cooler 7 together with the regulating valve V25, so that the intercooler 3 and the secondary cooler 4 connected in series downstream can always obtain sufficient volume flow.

[0257] To detect the temperature T100 of the compressed gas at the output of the compressor device, a temperature measuring site T86 is provided. In Figure 6 the separators Z1 and Z2, which can particularly be configured as swirl separators, and the condensate discharger K20 are also shown respectively. They can also be present in the remaining embodiments, even if they are not shown.

[0258] Some main aspects of the embodiment according to Figure 6 are summarized below. In Figure 6 the described embodiment, there are thus additional coolers 7, 8.

[0259] Here, there are again two cooling water circulation circuits 50 and 580.

[0260] The coolers 3, 4, 5, 7, 8 for stages 1, 2 and the cooler 6 are in the primary circulation circuit 50. Here, there is first a parallel connection of the oil cooler 5 for the cooler 6 for stages 1, 2 and the additional coolers 7, 8. The intercooler 3 and the secondary cooler 4 are connected in series thereafter. The intercooler and the secondary cooler are also in parallel connection.

[0261] The secondary circulation loop 580 cools the primary circulation loop 50 as needed here.

[0262] Figure 7 The embodiment of... basically corresponds to Figure 3 the construction of.... However, it is different in that a jacket cooler heat exchanger 6 is provided for the first jacket cooler 41 and the second jacket cooler 4, that is, for the jacket cooler 341 by means of which. The construction of the jacket cooling device and the cooling terminal by means of the jacket cooler heat exchanger 6 are realized as shown in Figure 6 ....

[0263] In Figure 7 ..., in addition, the intercooler 3 and the secondary cooler 4 are respectively independently connected to the primary cooling circulation loop 50 in a parallel connection. Here, however, in Figure 7 ... the parallel connection of the intercooler 3 and the secondary cooler 4 to the primary circulation loop is also obtained as in Figure 3 ..., and the described differences between Figure 3 and Figure 7 are basically constructive.

[0264] For Figure 7 the embodiment of..., but also for the remaining embodiments, the following advantages are obtained.

[0265] The specific power is improved by approximately 1%,..., 3% due to better jacket cooling and intercooling.

[0266] Higher heat recovery power is possible, and in some cases, there is little / no cooling water requirement.

[0267] Closed-loop control to a higher water discharge temperature T14 is feasible, that is, the possibility of presetting a higher water discharge temperature T14, that is, higher than the previous expected value (for example, 90 °C,..., 95 °C, instead of ~85 °C as before).

[0268] Higher operating safety can be achieved because the compressor can be better cooled as needed.

[0269] Easier start-up is possible because no manual balancing branch control valve is required.

[0270] The water distribution is adjusted automatically, especially seasonally, climate-related, ultimately pressure-related, speed-related.

[0271] More efficient use of cooling water is possible.

[0272] Smaller compressed air consumption can be achieved through the optimal compressed air temperature.

[0273] The following additional advantages are obtained.

[0274] It is possible to perform optimal closed-loop control of the mixed water discharge temperature T14 by using closed-loop control of the individual volumetric flow of each heat source.

[0275] The user can preset the water discharge temperature T14, the maximum compressed air discharge temperature T100, and, if necessary, the maximum pressure dew point.

[0276] The oil cooler always only receives as much water as required to achieve an optimal oil temperature.

[0277] The secondary cooler hardly affects the specific power. Therefore, the secondary cooler only receives as much water as required to achieve the desired, especially maximum, compressed air discharge temperature T100 or pressure dew point M85, and it does not boil, i.e., the temperature, such as T12, is kept below 110 °C.

[0278] Intermediate cooling has a large impact on the specific power, so as much water as possible is obtained.

[0279] Jacket cooling has the greatest impact on the specific power, so disproportionately more water is obtained. As a scale for closed-loop control, the following temperature correlation can be based on: T13 - T10 := 0.5 * (T11 - T10).

[0280] If a component temporarily requires better cooling, it can also be cooled better.

[0281] Figure 8 The embodiment of... basically corresponds to that in a slightly different view. Figure 6 The embodiment of... In Figure 8 In the view of..., in addition, a primary bypass 21 and a primary bypass regulating valve V19 are provided.

[0282] Here, in addition to the primary bypass regulating valve V19, a heat exchanger control valve V25 for the secondary cooler is provided, which should be understood as two alternative embodiments. Thereby, a plurality of optional implementation schemes should be shown more generally in the drawings.

[0283] The above-described embodiment with the primary bypass regulating valve V19 and the heat exchanger control valve V25 can still be realized. This embodiment is meaningful in special cases when warmer compressed air is required in winter. Then, the valves V28 and V25 must be closed for the secondary cooler so that insufficient water is supplied to the intermediate cooler and the secondary cooler without having to open the primary bypass regulating valve V19.

[0284] By means of the primary bypass regulating valve V19, it is possible to convey the part of the coolant that does not flow through the third secondary cooler 8 to the intermediate cooler 3 and the secondary cooler 4. As inFigure 6 as in Figure 8 The embodiment also proposes that the intermediate cooler 3 and the secondary cooler 4 are arranged in series connection or interconnected in the primary cooling circuit, but are connected in parallel with each other.

[0285] The temperature T85 can be recorded before the cooler 8.

[0286] For Figure 5 , 6 and the embodiment of 8, the following should be noted. In these three embodiments, the intermediate cooler 3 and the secondary cooler 4 are connected in series with the primary cooling circuit, where the primary bypass regulating valve V19 is ignored for the sake of simplicity in the following description. The intermediate cooler 3 and the secondary cooler 4 thus jointly obtain the complete coolant flow, that is, the total coolant flow of the primary cooling circuit 50, because this is caused by the series connection. However, in all the three embodiments described, a series connection between the intermediate cooler 3 and the secondary cooler 4 is still provided. Therefore, it has been recognized that individual control mechanisms for the intermediate cooler 3 and the secondary cooler 4, that is, the regulating valves V11 and V12 here, are still advantageous. In addition, that is, it is possible to control what proportion of the total coolant flow of the primary cooling circuit flows through the intermediate cooler 3 on the one hand and through the secondary cooler 4 on the other hand. Therefore, it is possible to achieve the distribution of cooling on the one hand between these two compressor stages and on the other hand in the region directly behind the second compressor stage.

[0287] For Figure 8 the embodiment and other embodiments, the following advantages are obtained:

[0288] Maximum heat recovery is possible during sufficient heat dissipation and operation without cooling water. Therefore, it is considered that the secondary cooling system 11 does not have to be used, but it is possible to be prepared for the case where less heat is required at one time or the compressor requires better cooling.

[0289] As an application, the connected building heating system is proposed. The building heating system can have the following effects. In winter, all the heat can be utilized via the heat exchanger 10. While in summer, less heat is required, but the heat still has to be removed. This is then carried out via the primary-secondary heat exchanger 9, the secondary cooling system 11 and the valve V10.

[0290] According to the temperature requirements and alternatives, about 10%,..., 30% more waste heat utilization may be possible. The maximum waste heat utilization is possible at a water inlet temperature that is about 5K,..., 10K higher.

[0291] A very high water discharge temperature T14 is possible, especially up to about ~95 °C.

[0292] In the case of high volumetric flow rates, sufficient jacket cooling and oil cooling of the heated water is possible, in particular via a primary water system with an inflow temperature or an outflow temperature T10 and T14.

[0293] A sufficient dew point can be achieved because the cooler 7 receives cold heated water in large volumetric flow rates.

[0294] When required, a low compressed air discharge temperature is possible because the cooler 8 receives cold heated water.

[0295] Figure 9 A schematic, partially cut-away view of a compressor device 900 is shown, which has first and second compressor stages 901 or 907. In this regard, Figure 10 An enlarged view of the first compressor stage 907 is shown. With reference below to Figure 9 and additionally with reference to Figure 10 as long as the first compressor stage is being elucidated.

[0296] Figure 9 A dry screw compressor is thus shown, which essentially forms the compressor device 900. The first compressor stage 901 thus performs the compression of the first stage during operation. In this regard, the first compressor stage 901 has a housing 902 and a jacket-cooled coolant channel 903, which is shown more clearly especially in Figure 10 .

[0297] For the compression of compressed gas, in particular compressed air, a compressor screw 904 is provided, which engages into one another for compression. The compressor screw is driven via a drive shaft 905 of the corresponding compressor stage. A second compressor stage 907, which further compresses the gas, in particular the compressed air, compressed in the first compressor stage, has a housing 909 with a coolant channel 908 and a compressor screw 910, which is driven via a drive shaft 911.

[0298] The two drive shafts 905 and 911 are driven via a common drive motor 906, and in this regard a transmission 912 is provided, which distributes the drive power of the drive motor to these two drive shafts 905 and 911 in order to thereby drive the compressor screws 904 and 910.

[0299] Via the jacket cooling achieved by means of the coolant channels 903 and 908, the two compressor stages 901 and 907 can be cooled. In this regard, a cooling medium, in particular cooling water, flows through the coolant channels 903 and 908, and this can be controlled jointly or individually.

[0300] According to the invention, at least according to one aspect, the following aspect is particularly emphasized.

[0301] In particular, a compressor with water-cooled multi-stage dry compression is proposed, which compressor includes at least one intercooler, a secondary cooler, an oil cooler and a compressor cooler, in particular a jacket cooler, for cooling at least one compressor stage housing which can also be referred to as a housing cooler. The intercooler and the secondary cooler each form a compressed gas cooler.

[0302] It is proposed that in each of said cooling devices, i.e. in each of said coolers, the water flow rate for heat dissipation can be closed-loop controlled individually via its own closed-loop control mechanism, in particular a control valve or a controllable pump. The closed-loop control mechanism can also be referred to as a control mechanism.

[0303] The following aspects can additionally be proposed. At least two compressed air secondary coolers can be provided after the second compressor stage. At least one compressed air dryer can be provided together with a compressed air cooler for the dried compressed air downstream. The device for cooling at least one compressor housing is configured as a jacket cooling device or a jacket cooler, and / or a heat exchanger for such a jacket cooling device is provided.

[0304] The closed-loop control mechanism or the control mechanism is provided as a closed-loop control of the coolant flow of each heat exchanger for closed-loop controlling the water volume flow as a separate regulating valve for each individual water flow path. In particular, a control device for the coolant is provided for each cooler. Each cooler can respectively have a supply branch through which the cooler is supplied with coolant. This respectively includes the introduction and extraction of the coolant. Each supply branch can have an inlet and an outlet. Preferably, a control mechanism is provided in the supply branch of each cooler respectively. The control mechanism can be respectively in the inlet or the outlet. The supply branches of each of the individual coolers can be arranged in parallel with some or all of the supply branches of the remaining coolers.

[0305] The control mechanism or the closed-loop control mechanism for closed-loop controlling the water volume flow of each heat exchanger can be configured as a separate controllable pump for each parallel branch, i.e. in particular for each supply branch. The control mechanism or the closed-loop control mechanism can be arranged to respectively closed-loop control one device each, in particular the cooler for at least one compressor housing. A parallel connection of the oil cooler and at least one of said devices, in particular the cooler for cooling at least one compressor housing, is proposed.

[0306] It is proposed that the control mechanism or the closed-loop control mechanism is closed-loop controlled or coordinated by a central or common control unit.

[0307] Different wiring variants for jacket cooling can be proposed. One of them is the parallel connection of an oil cooler and a jacket cooling device or jacket cooler. Another is a heat exchanger provided with an oil cooler and a jacket cooling device, enabling separate or independent closed-loop control of the oil temperature and the temperature of the jacket cooling device.

[0308] Preferably, a screw compressor is provided as the compressor. Water or a water-ethylene glycol mixture can be used in particular as the coolant.

[0309] For controlling the control mechanism or closed-loop control mechanism for the temperature of the jacket cooling device in a closed loop, when a heat exchanger is provided for separation (which can also be referred to as system separation), especially for separating the jacket cooling circuit from the primary cooling circuit, two variants can be proposed in particular. According to the first variant, open-loop control or closed-loop control is carried out directly by open-loop controlling or closed-loop controlling the coolant flow, especially the water flow rate, through the jacket cooling device. According to the second variant, open-loop control or closed-loop control is carried out indirectly by open-loop controlling or closed-loop controlling the coolant flow or water flow rate through the heat exchanger that exchanges heat with the coolant, especially the coolant of the jacket cooling device.

[0310] If there is no heat exchanger for system separation, the control mechanism or closed-loop control mechanism can be used for open-loop control or closed-loop control of the temperature of the jacket cooling device.

[0311] According to other aspects, a dry-compression compressor is proposed, which has a liquid-cooled heat exchanger formed by at least one intercooler, at least one secondary cooler, at least one oil cooler, and at least one device for cooling at least one compressor housing. For this, individual regulating valves or control valves are provided for closed-loop control of the water volume flow for each individual heat exchanger. The open-loop control or closed-loop control of the coolant flow can be configured for each embodiment as the open-loop control or closed-loop control of the volume flow of the corresponding coolant, especially as the open-loop control or closed-loop control of the water volume flow when water is used as the coolant. The temperatures of at least one intercooler, at least one secondary cooler, at least one oil cooler, and at least one device for cooling at least one compressor housing (which can be referred to as a housing cooler) are closed-loop controlled independently of each other. This is carried out in particular by open-loop controlling or closed-loop controlling the flow rate of the coolant through the mentioned coolers or devices respectively.

[0312] The mixed water discharge temperature, designated as T14 in the drawing, i.e., the discharge temperature of the total coolant flow, is adjusted to a desired, in particular preset value, in such a way that the water volume flows through the heat exchangers connected in parallel are adjusted independently of one another to individual, possibly different temperatures, such that the desired total water discharge temperature T14 is obtained after the individual sub-volume flows, i.e., the individual coolant flows of the respective coolers, have been combined. It is proposed for this purpose that the control means, in particular valves, in particular regulating valves, be actuated or controlled by a common and / or central control unit.

[0313] A closed-loop control can be provided as follows. The oil cooler always receives exactly the amount of water required to achieve the desired oil temperature (e.g., 70 °C). The compressed air aftercooler, in particular the aftercooler or the first aftercooler, always receives exactly the amount of water required not to exceed the desired maximum compressed air discharge temperature, not to exceed the desired maximum pressure dew point and not to exceed the maximum permitted water temperature (e.g., 100 °C).

[0314] The water discharge temperature leaving the jacket cooling device, i.e., leaving the housing cooler, is adjusted such that it is less than the water discharge temperature leaving the intercooler.

[0315] According to a first aspect, the intercooler and the jacket cooling device receive as much or as little water as required in order to achieve the desired mixed water discharge temperature.

[0316] According to a second aspect, the intercooler receives as much or as little water as required in order to achieve the desired mixed water discharge temperature T14.

[0317] It is proposed to carry out a closed-loop control such that the temperature difference between the water inlet and the water outlet of the jacket cooling device is approximately half as large as the temperature difference between the water inlet and the outlet of the intercooler. A value of half the temperature difference has proven to be advantageous. In particular, it has proven to be a good compromise. However, the optimal value of the factor can also depend on which of the temperature differences T13 - T10, T15 - T10 and T23 - T10 is set relative to T11 - T10.

[0318] Furthermore, according to each aspect, it is proposed that the mixed water discharge temperature be maintained at a pre-determined or preset value. The value can be changed as a function of the external temperature, and a heating curve can be preset for this purpose.

[0319] The following method steps can be provided for setting the flow rate. These method steps can be prioritized in the order mentioned:

[0320] 1. Ensure the compressed air supply, i.e., interference-free operation.

[0321] 2. Ensure the compressed air quality, i.e., the preset pressure dew point and compressed air temperature.

[0322] 3. Open-loop control or closed-loop control is then carried out such that the desired water discharge temperature T14 is achieved.

[0323] 4. In some aspects, it is proposed that the provision of the desired thermal power is carried out via the primary water system, i.e., the primary cooling circuit, wherein re-cooling via the secondary water system is proposed, which can be carried out via a regulating valve, in particular the regulating valve V10 shown in the drawings.

[0324] 5. The control is then carried out such that the minimum power consumption of the compressor is achieved.

[0325] Furthermore, according to one aspect, a closed-loop control of the pressure dew point is proposed, provided that a compressed air dryer is used and measurement values for humidity are available. For this, the pressure dew point or the absolute humidity or the relative humidity can be measured directly.

[0326] When using a cold dryer, it is also possible to measure the temperature at cold locations and directly infer the pressure dew point therefrom.

[0327] If the pressure dew point is too high after drying, the control device is set such that one or more heat exchangers before the dryer, i.e., at least one of the compressed gas coolers upstream of the dryer, receive more and / or colder cooling water. In particular, the coolant flow through at least one compressed gas cooler is increased.

[0328] When using an adsorption dryer with regeneration by compressor heat, the intercooler receives less water, i.e., less coolant, in order to achieve a higher discharge temperature leaving the compressor, in particular leaving the second compressor stage, in order to use it for the regeneration of the dryer.

[0329] In the closed-loop control of the water valve, the following measured temperatures are particularly taken into account, where the reference numerals refer to the drawings in which they are drawn:

[0330] - The compressed air discharge temperature T100 leaving the compressor device, which according to the embodiment can be the compressed air discharge temperature leaving the last heat exchanger or leaving the dryer, thus being the temperature of the output compressed air, in particular when the compressed air is used for further use, where for T100 the measured value of temperature location T85 or T52 or T51 or T4 can be adopted, also depending on where the compressor device ends;

[0331] - The oil temperature, in particular the oil inlet temperature in the oil cooler T60,

[0332] - The oil temperature upstream of the oil cooler,

[0333] - The oil discharge temperature leaving the compressor stage,

[0334] - The air discharge temperature T51 leaving the secondary cooler,

[0335] - The air discharge temperature T31 leaving the intermediate cooler,

[0336] - The water discharge temperature T11 leaving the intermediate cooler,

[0337] - The water discharge temperature leaving the secondary cooler T12,

[0338] - The water discharge temperatures T13, T15, T23 leaving the jacket cooling device or the heat exchanger of the jacket cooling device,

[0339] - The air and water discharge temperatures leaving the optional additional heat exchanger 7, namely the temperatures T52 and T25, and the air and water discharge temperatures leaving the heat exchanger after the dryer 8, namely the temperatures T86 and T28, and

[0340] - The air discharge temperatures T2 and T4 leaving the compressor stage.

[0341] According to one aspect, an embodiment of heat recovery is proposed. Via a water-water heat exchanger, the water inlet temperature T10 for the heat exchanger in the primary cooling circuit is closed-loop controlled via the regulating valve V10. Thereby, the heat recovery power is regulated.

[0342] If the water inlet temperature T10 is smaller compared to the average value, then the electrical power consumption of the compressor is correspondingly slightly smaller and the available waste heat power is significantly smaller, due to the smaller water volume flow through the primary water circulation circuit.

[0343] If the temperatures T9 and T10 are low, then the waste heat power can be higher. The waste heat power only becomes significantly smaller when T10 is less than T9, i.e., when heat is withdrawn via the heat exchanger 9 and the secondary cooling system 11.

[0344] Other aspects can be proposed.

[0345] Waste heat utilization can be proposed, where all the heat of the compressor can be withdrawn into the primary water system (e.g., heating water). This means that the waste heat of the heat exchanger can be withdrawn via the primary water system according to the heat demand and the temperature profile. In other embodiments, a part of the waste heat can be withdrawn via the secondary cooling system.

[0346] However, a small part of the waste heat is also output via the cooling air. Another small part of the compressed heat can be withdrawn via the compressed air.

[0347] Re-cooling of the primary water (e.g., heating water) via a secondary circulation circuit (e.g., cooling water) can be proposed:

[0348] - If on the building side, for example, in a connected heating device or other building-side connected components, less heat from the primary circulation circuit is required,

[0349] - In order to improve the specific power, and / or

[0350] - If individual components of the compressor require better cooling and the input temperature, designated as T9 in the figure, of the supplied primary cooling circuit is too high for this.

[0351] According to one aspect, a complete internal circuit is provided, which has a pump, an expansion tank, a bypass and optionally other elements. Thereby, the compressor can also operate without being connected to the building-side primary water system (for example, when the heating system fails).

[0352] In this aspect, water circulates only internally on the primary side through the pump 12b and the bypass 21. Figure 4 This aspect is illustrated by way of example.

[0353] In Figure 8 an aspect is shown in which a bypass V19 can be provided as a variant.

[0354] This aspect is proposed when the intercooler and the secondary cooler together require more water than the heat exchanger connected upstream. This can occur in extreme cases during cold start when the control valves V16, V13, V28, V25 are closed, but the control valves V11 and V12 are open, especially fully open.

[0355] According to one aspect, it is proposed to close-loop control the jacket cooling for optimal cooling. Good cooling can thereby be achieved because the jacket cooling has a large influence on the specific power, i.e., in particular on the power / volume flow of the compressor. It is proposed here not to regulate the cooling too strongly in order to prevent excessive wear of the compressor stage, especially the wear of the rotor and the housing cladding of the compressor stage.

[0356] In particular, the idea here is that the cooling of the compressor stage should be as good as possible, but also as constant as possible in the long term. In the short term, simply the colder the better, as long as no condensate appears.

[0357] However, the low temperature must then also be maintained permanently. Since this is usually not possible, it may be better to cool only moderately in winter so that the temperature can also be reached in summer.

[0358] If the stage is "too well", i.e., cooled too strongly, then the housing becomes smaller and the cladding of the housing and the rotor wears further. If this is maintained permanently, this may be good. However, if the housing or the jacket cooling device then heats up again and thus becomes larger, then the gap becomes larger and the compressor becomes particularly worse.

[0359] As one aspect, it is proposed to minimize the compressed air temperature before entering the second compressor stage. The temperature is obtained at the temperature measurement location T31 in Figure 8 or can also be understood as T31. This aspect is proposed in order to minimize the specific power of the compressor. The intercooler that cools part of the compressed air at the temperature measurement location obtains as much water as possible for this purpose. For this, it is proposed that the coolers 7 and 8 and the oil cooler only obtain as much water as needed. This is set in order to keep the preheating of the coolant at the measurement location T19 in Figure 8 before entering the intercooler small. The secondary cooler 4 obtains as little water as possible here, but enough so that the temperature at the output of the secondary cooler 4 at the measurement location T12 in Figure 8 is not too high. The expected value for the optimal compressed air discharge temperature and the pressure dew point should be achieved as much as possible.

[0360] According to one aspect, it is proposed to adjust the oil temperature upstream of the oil cooler to a preset expected value. For this, it has been recognized that the preset maximum temperature of the oil at the measurement location T60 in Figure 7 before the oil cooler is more important for the service life of the oil, the bearings and the transmission than the incoming temperature at the measurement location T66 in Figure 7 downstream of the oil cooler. It has been recognized that this causes a colder incoming temperature at the temperature measurement location T66 in the case of a high oil temperature rise. Thereby, the bearings can be better cooled under high load or high temperature rise. Thus, it is possible that the not yet cooled and thus high oil temperature, especially the oil temperature at T60, remains constant, while the cooled and thus low oil temperature, especially the oil temperature at T66, fluctuates depending on the bearing load and possibly other loads.

[0361] The following aspects are also mentioned, by means of which the invention, at least its aspects, stand out from the prior art or have been recognized according to the invention.

[0362] The jacket cooling device must cool or be cooled as evenly and well as possible. It is optimal to cool persistently and constantly well. However, in practice, the water temperature usually fluctuates significantly.

[0363] Some solutions in the prior art (see WO 2022 / 163079 A) thus cool the jacket cooling device by means of preheated water connected in series with the oil cooler in order to avoid overcooling the compressor housing so much that it becomes too small, which would cause undesirably strong wear of the rotor and the housing cladding of the compressor stage. The principle of this wear is derived in the patent application EP 3399191 A1.

[0364] Other solutions in the prior art, although cooling the jacket cooling device with cold (unpreheated) water, cannot be independently closed-loop controlled. Although very good specific values can be obtained in the case of cold cooling water, this also causes stronger wear of the rotor and the housing cladding. Thus, in the subsequent (normal) operation at higher water temperatures, the gap becomes unnecessarily large, resulting in more backflow, which negatively affects the specific power of the compressor.

[0365] By closed-loop controlling the flow rate through the jacket cooling device, the present invention can prevent the jacket cooling device from being over-cooled when the water temperature is too low. Therefore, according to the present invention, more uniform and better cooling can also be achieved with preheated water, which durably and positively affects the specific power of the compressor.

[0366] According to the present invention, in particular, the jacket cooling device is now cooled with cold water, i.e., unpreheated water, and independently of other heat exchangers, the flow rate through the jacket cooling device is closed-loop controlled, so as to close-loop control the jacket cooling device temperature T13 or the housing temperature and the housing size.

[0367] According to the present invention, it is particularly proposed to use a tightly closed valve. Therefore, the flow through each parallel branch can also be completely blocked. This is the case, for example, during shutdown, but also during cold start. Here, the intercooler and the secondary cooler have already been flowed through, while the oil cooler and the jacket cooling device do not even receive water for some initial time until the corresponding operating temperature is reached.

[0368] The separate closed-loop control of the jacket cooling device is therefore an aspect proposed.

[0369] In addition, the following are aspects according to the present invention.

[0370] It is proposed to perform open-loop control or closed-loop control of the housing cooling device, in particular the jacket cooling device, separately from the remaining cooling devices, wherein the flow rate and / or the temperature of the coolant is controlled.

[0371] In addition, it is proposed to perform open-loop control or closed-loop control of the discharge temperature of the common coolant flow in the primary cooling circuit of the compressor device in particular. This temperature can also be referred to as the mixed discharge temperature and is plotted at the temperature measurement point T14 in the drawings. For this purpose, it is proposed that the mentioned discharge temperature is executed by a plurality of control means, in particular parallel closed-loop control means, each of which is adjusted to a different temperature.

[0372] It has been recognized and proposed according to the present invention in one aspect that, on the one hand, in relation to the relationship between the current electricity price and the current heat price, and on the other hand, in relation to the difference between the primary heat recovery temperature and the secondary cooling water temperature, the jacket cooling device is operated with the primary hotter heat recovery water or the secondary colder cooling water.

[0373] As the electricity price, the price per kWh, i.e., for example, in € / kWh. The heat price mentioned can be related to the gas price including other operating costs and efficiency, or to other prices of primary energy sources.

[0374] Based on the following concept here, in summer it is considered that other more beneficial heat sources, in particular other primary energy carriers, are available.

[0375] It should be noted here that costs can also be estimated for the waste heat of the compressor. The higher the temperature level, the more expensive the waste heat of the compressor, because at the same time the specific power [kwh / m 3 deteriorates.

[0376] However, it has been recognized that the waste heat of the compressor can generally be assumed to be more beneficial than generating heat via a gas burner.

[0377] In particular, when the heat demand is smaller than the maximum possible heat supply of the compressor unit, it is proposed to optimize the heat supply.

[0378] This optimization can be carried out by reducing the temperature T10 in order to thereby reduce the temperature T31. Depending on the past trend or the clearance and temperature level of the compressor, a reduction in the temperature T13 or the temperature T15 can also be meaningful. Both are presented here as possible aspects.

[0379] These two measures can reduce the power consumption and at the same time increase the mass flow of the compressed gas, so that the specific power decreases.

[0380] One aspect of the invention is the closed-loop control of the jacket cooling device. This exists especially in dry-compression screw compressors. In compressors with oil injection or water injection, this closed-loop control may be unimportant or less important. Therefore, it is particularly proposed to use dry-compression screw compressors.

[0381] Turbo pistons, scroll pistons, rotary pistons, toothed pistons, and reciprocating pistons can be used and are examples of compressors for dry compression.

[0382] It has been particularly recognized that in dry-compression screw compressors, the jacket cooling device has particular significance. The invention, at least its aspects, are therefore particularly designed for use with dry-compression screw compressors.

Claims

1. A compressor device, comprising: - a compressor for compressing a gas to produce compressed gas, in particular compressed air; and - a cooling device, and the cooling device comprises: - an oil cooler for cooling the oil heated by the compressor; - at least one compressed gas cooler for cooling the gas fully or partially compressed into the compressed gas, and at least one casing cooler for cooling the casing or a part of the casing of the compressor, wherein The oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each provided for cooling by means of a coolant flow consisting of a liquid coolant, in particular water, and wherein - Individual, controllable control mechanisms are provided for the coolant flow of the oil cooler, the coolant flow of at least one compressed air cooler of the at least one compressed gas cooler and the coolant flow of at least one housing cooler of the at least one housing cooler, respectively, so as to individually control each of the coolant flows, so that the cooling power of the oil cooler, at least one of the at least one compressed gas cooler and at least one of the at least one housing cooler can be individually controlled.

2. The compressor device according to claim 1, It is characterized in that - the oil cooler, - said at least one compressed gas cooler, wherein at least one compressed gas cooler, and - the at least one housing cooler, wherein at least one housing cooler connected to a common coolant circuit, in particular a primary cooling circuit, in particular in a parallel connection.

3. The compressor device according to claim 1 or 2, It is characterized in that - the compressor has a plurality of compression stages, and The at least one compressed gas cooler has an intercooler and a postcooler, wherein - the intercooler cools the gas partially compressed into compressed gas between the first compression stage and the second compression stage, and - the aftercooler cools the compressed gas at the output of the compressor after passing through a plurality of compression stages, and / or The intercooler and / or the aftercooler each have an individually controllable control device.

4. A compressor device according to any one of the preceding claims, It is characterized in that The control devices each have a controllable valve and / or a controllable pump.

5. A compressor device according to any one of the preceding claims, It is characterized in that The at least one housing cooler - having at least one jacket cooler, which has in particular: - Two sub-jacket coolers connected in series for cooling a compressor stage each, said sub-jacket coolers being arranged for cooling with the same cooling flow and for controlling said cooling flow by means of the same control mechanism.

6. A compressor device according to any one of the preceding claims, It is characterized in that - a common control device is provided for coordinated control of the coolant flows, in particular The common control device is provided for controlling the control device and is connected to the control device.

7. A compressor device according to any one of the preceding claims, It is characterized in that - the compressor is a dry compression compressor, and / or - is a screw compressor which is constructed to compress gas by the movement of two screws engaging with each other.

8. A compressor device according to any one of the preceding claims, It is characterized in that at least one further or two further compressed gas coolers are provided, which are arranged downstream of the compressor with respect to the flow direction of the compressed gas in order to further cool the compressed gas there, wherein - the at least one further or two further compressed gas coolers - each using a coolant flow controlled by its own individual control mechanism, and connected to the same or identical primary cooling circuit as the oil cooler, the at least one compressed gas cooler and / or the at least one housing cooler, in particular in parallel, and / or A connection to a second medium cooling circuit as a secondary cooling circuit, which operates independently or is coupled to the primary cooling circuit, in particular via a heat exchanger.

9. A compressor device according to any one of the preceding claims, It is characterized in that - the oil cooler, the at least one compressed gas cooler and / or the at least one casing cooler are respectively has a heat exchanger or is designed as a heat exchanger and is provided for controlling a corresponding coolant flow as a cooling flow through the corresponding heat exchanger by means of a corresponding control device.

10. A compressor device according to any one of the preceding claims, It is characterized in that The compressor device, in particular the cooling device, is designed to control the coolant flow individually as a function of the temperature, in particular The control is performed as a function of at least one temperature measured, in particular by means of a sensor device, which temperature is selected from the following list: - oil temperature, in particular the oil temperature of the oil heated by the compressor, - compressed gas temperature, - the jacket temperature of the coolant flowing through the casing jacket of the compressor, - the temperature of the coolant, - Oil entry temperature, as the temperature of the oil entering the oil cooler, - aftercooler-gas discharge temperature, as the temperature of the compressed gas discharged from the aftercooler or said aftercooler, - intercooler-gas discharge temperature, being the temperature of the compressed gas discharged from the intercooler or said intercooler, - intercooler-coolant discharge temperature, being the temperature of the coolant discharged from the intercooler, - Aftercooler-coolant discharge temperature, being the temperature of the coolant discharged from the aftercooler, - Jacket cooler-coolant discharge temperature, as the temperature of the coolant discharged from the jacket cooler or said jacket cooler, a respective gas or coolant outlet temperature as the temperature of the compressed gas or the coolant outlet from at least one heat exchanger, - compressor-gas discharge temperature, as the temperature of the compressed gas discharged from a compressor stage of the compressor and / or from the compressor and / or from the compressor device, and - cooling circuit-coolant discharge temperature, as the temperature of the coolant when it is discharged from the primary and / or secondary cooling circuit or the primary and / or secondary cooling circuit, and / or The compressor device is designed to control at least one coolant flow as a function of a pressure dew point of the compressed gas, which is measured, in particular, by means of a sensor device.

11. A compressor device according to any one of the preceding claims, It is characterized in that The compressor device, in particular the cooling device, is arranged to control the coolant flow such that - Closed-loop control of the total coolant discharge temperature or the total coolant discharge temperature as the temperature of the coolant discharged from the primary and / or secondary cooling circuit or the primary and / or secondary cooling circuit to a predeterminable desired discharge temperature.

12. A compressor device according to any one of the preceding claims, It is characterized in that The compressor device, in particular the cooling device, is provided for: - controlling the coolant flow of the oil cooler by means of an associated control mechanism so that a preset oil temperature is adjusted, and / or - one of the at least one compressed gas coolers, in particular the aftercooler or the coolant flow of the aftercooler is controlled by means of an associated control device in such a way that a predefined compressed gas outlet temperature is not exceeded and / or not dropped below, and / or - a coolant flow control of one of the at least one casing coolers, in particular the jacket cooler or the jacket cooler, such that a coolant outlet temperature of the coolant is lower than a coolant outlet temperature of one of the at least one compressed gas coolers, in particular the intercooler or the intercooler, and / or - the coolant flow of one of the at least one housing cooler, in particular the jacket cooler, is controlled in such a way that the difference between the coolant discharge temperature when the coolant is discharged from the housing cooler and the coolant inlet temperature when the coolant enters the housing cooler is - is below a predeterminable first value, and / or - is above a second predeterminable value, and / or - between a predeterminable third value and a fourth value.

13. A method for operating a compressor device, the compressor device comprising: - a compressor for compressing a gas to produce compressed gas, in particular compressed air; and - a cooling device, and the cooling device comprises: - an oil cooler for cooling the oil heated by the compressor; - at least one compressed gas cooler for cooling the gas fully or partially compressed into the compressed gas, and at least one casing cooler for cooling the casing or a part of the casing of the compressor, wherein The oil cooler, the at least one compressed gas cooler and the at least one housing cooler are each cooled by a coolant flow consisting of a liquid coolant, in particular water, and wherein Each coolant flow is controlled individually by means of an individual, controllable control device, so that the cooling capacity is controlled individually for the oil cooler, the at least one compressed gas cooler and the at least one housing cooler.

14. Method for operating a compressor arrangement according to claim 13, It is characterized in that Use of a compressor device according to any one of claims 1 to 12.

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